EJBR2019v9i4art202 ISSN 2449-8955 European Journal of Biological Research Review Article European Journal of Biological Research 2019; 9(4): 202-244 DOI: http://dx.doi.org/10.5281/zenodo.3528366 Essential oils as green pesticides of stored grain insects Mukesh Kumar Chaubey Department of Zoology, National Post Graduate College, Barahalganj, Gorakhpur - 273 402, Uttar Pradesh, India Correspondence: mgpgc@rediffmail.com Received: 15 May 2019; Revised submission: 04 October 2019; Accepted: 30 October 2019 http://www.journals.tmkarpinski.com/index.php/ejbr Copyright: © The Author(s) 2019. Licensee Joanna Bródka, Poland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/) ABSTRACT: Essential oils are naturally occurring phytochemicals produced as secondary metabolite in plants. These are complex mixtures of volatile compounds and generally contain twenty to sixty individual compounds in different concentrations. They are lipophilic in nature and have density lower than water. These interfere with basic metabolic, biochemical, physiological and behavioral functions of insects. Several essential oils and its constituents have been established for their repellent, antifeedant, ovicidal, oviposition inhibitory and developmental inhibitory activities in insects. These insecticides probably interfere with the respiratory and nervous system of the insect to exert its actions. These essential oils provide an alternative source of insect control agents because they contain a range of bioactive chemicals, most of which are selective and have little or no harmful effect on the environment and the non-target organisms including human. Essential oils based formulations can be used as alternative tools in stored-grain insect management. Keywords: Essential oils; Terpenes; Stored grain insects; Antifeedants; Insect growth regulators. 1. INTRODUCTION Plant derived essential oils also known as volatile or ethereal oils are mixtures of odorous and volatile compounds. These are natural complex secondary metabolites characterized by a strong odour. These have generally lower density than that of water [1]. About 10% of the plant species are known to contain essential oils. There are 17,500 aromatic plant species among higher plants and approximately 3,000 essential oils are known out of which 300 oils are commercially used for pharmaceuticals, cosmetics and perfume industries apart from pesticidal application [1, 2]. Genera capable of producing essential oils are distributed in a limited number of families such as Apiaceae, Asteraceae, Compositae, Cupressaceae, Labiatae, Lauraceae, Myrtaceae, Piperaceae, Poaceae, Rutaceae and Zingiberaceae (Table 1). Essential oils are extracted from leaves, flowers, peels, seeds, wood, berries, resins, rhizomes and roots. Essential oils are produced and accumulated in specialized structures as they are toxic to cells. There are several specialized secretory structures like oil cells, oil glands, ducts and trichomes that are discretely distributed within the plants from flowers to roots. According to Gottlieb and Salatino, essential oil production and secretory structures formation are closely connected [3]. For example, oil globules within membrane of secretory cell of rhizome in Zingiber officinale, peltate gland on leaves of Lippia scaberrima and secretory cavity in Citrus peel are responsible for biosynthesis and storage of essential oils [4-6]. Endogenous factors like development stage of whole plant and specific organs and exogenous factors both biotic and abiotic can Chaubey Essential oils as green pesticides of stored grain insects 203 European Journal of Biological Research 2019; 9(4): 202-244 alter essential oil production [7-9]. Sangwan et al. have indicated that ontogeny, photosynthetic rate, photoperiod, light quality, climatic and seasonal changes, nutrition, humidity, salinity, temperature, soil nature, storage structures and growth regulators are the factors that affect the production of essential oils both quantitatively and qualitatively [7]. Table 1. Some common essential oil producing plants. Botanical name Family Acorus calamus Acoraceae Cananga odorata Anonaceae Anethum graveolens Apiaceae Angelica officinalis Apium graveolens Carum carvi Coriabdrum sativum Cuminum cyminum Ferula galbaniflua Foeniculum vulgare Levisticum officinale Petroselinum sativum Pimpinella anisum Trachyspermum ammi Acorus calamus Araceae Betula pendula Betulaceae Adnsonia digitata Bombacaceae Boswellia carteri Burseraceae Canarium luzonicum Commiphora myrrha Cassia fistula Caesalpiniaceae Abelia floribunda Caprifoliaceae Artemisia annua Compositae Artemisia dracunculus Calendula officinalis Chamaemelum nobile Chrysanthamum parthenium Tagetes erecta Brassica nigra Cruciferae Cochleria armoracia Cupressus sempervirens Cupressaceae Juniperus oxycedrus Thuja spp. Gaultheria procumbens Ericaceae Pelargonium spp. Geraniaceae Cymbopogon citratus Graminae Cymbopogon martini Cymbopogon nardus Chaubey Essential oils as green pesticides of stored grain insects 204 European Journal of Biological Research 2019; 9(4): 202-244 Botanical name Family Calamintha vulgaris Labiatae Hyssopus officinalis Lavandula augutifolia offinalis Lavandula spica Mellisa officinalis Mentha piperita Ocimum basilicum Ocimum sanctum Origanum majorana Origanum vulgare Orthodon punctulatum Pogostemon cablin Rosemarinus officinalis Salvia officinalis Satureja hortensis Thymus spp. Cinnamomum camphora Lauraceae Cinnamomum tamala Cinnamomum zeylanicum Laurus nibilis Sassafras albidum Myroxylon balsamum Leguminosae Myroxylon toluferum Trigonella foenum-graecum Allium cepa Liliaceae Allium sativum Illicium verum Magnoliaceae Acacia armata Mimosaceae Eucalyptus spp. Myrtaceae Eugenia earyophyllata Melaleuca alternifolia Melaleuca leucadendron Melaleuca viridiflora Myrtus communis Pimenta acris Pimenta officinalis Jasminum officinale Oleaceae Pandanus fasicularis Pandanaceae Piper nigrum Piperaceae Piper longum Piper cubeba Piper japonicum Rosa spp. Rosaceae Chaubey Essential oils as green pesticides of stored grain insects 205 European Journal of Biological Research 2019; 9(4): 202-244 Botanical name Family Aegle marmelos Rutaceae Citrus aurantifolia Citrus aurantium Citrus aurantium bergamia Citrus aurantium bigaradia Citrus aurantium sinensis Citrus limon Citrus reticulata Murraya koenigii Santalum album Santalaceae Cestrum nocturnum Solanaceae Stryrax benzoin Stryraceae Ageratum conyzoides Umbelliferae Daucus carota Lippia citriodora Verbenaceae Lantana camera Curcuma longa Zingiberaceae Elettaria cardamomum Zingiber officinale The total essential oil content of plants is generally very low and rarely exceeds 1%, but in some cases like clove (Syzygium aromaticum) and nutmeg (Myristica fragrans), it reaches up to 10% [10]. Due to presence of double bonds and functional groups like hydroxyl, aldehyde, ester in their molecular structures, essential oils are readily oxidizable by light, heat and air [11, 12]. These oils are stored as micro droplets in different glands of plants. After diffusing through glands, oil droplets spread over the surface of plant parts before evaporating and spreading in air. The most odoriferous plants are found in tropics where solar energy is greatest. There are numerous reports on differences of oil content and composition in aromatic plants due to seasonal variation. Microclimatic factors such as temperature, rainfall distribution and geographical features especially altitude also contribute to differences in chemotype of certain essential oil bearing plants. The type and nature of oil constituents and their individual concentration levels are important attributes particularly in terms of biological activities of the essential oils [13]. Vekiari et al. have reported seasonal variation in amounts of neryl acetate, geranyl acetate and citronellal in leaves and peel of certain lemon varieties [14]. Maximum values of compounds are obtained during spring season as compared to winter season [15]. 2. CHEMICAL COMPOSITION OF ESSENTIAL OILS Essential oils are highly complex mixtures of volatile compounds and may contain about 20-60 individual compounds in different concentrations. Each essential oil is characterized by two or three major components present in relatively high concentrations (20-70%) as compared to others components present in trace amounts. Generally, these major components determine the biological properties of essential oils. For example, carvacrol (30%) and thymol (27%) are the major components in Origanum compactum essential oil, linalol (68%) in Coriandrum sativum essential oil, 1,8-cineole (50%) in Cinnamomum camphora essential oil, phellandrene (36%) and limonene (31%) in Anethum graveolens leaf essential oil, carvone (58%) and limonene (37%) in A. graveolens seed essential oil, and menthol (59%) and menthone (19%) of Mentha piperita essential oil. The fragrance and chemical composition of essential oils can vary according to geo- Chaubey Essential oils as green pesticides of stored grain insects 206 European Journal of Biological Research 2019; 9(4): 202-244 climatic location and growing conditions (soil type, climate, altitude and amount of water available), season (before or after flowering), time of day when harvesting is achieved, genetic composition of the plant etc [7]. Therefore, all these factors influence the biochemical synthesis of essential oils in a given plant. Thus, same species of plant can produce a similar essential oil, however, with different chemical composition, resulting in different biological activities. Essential oil components can be classified into two groups, viz. volatile fraction and nonvolatile residue: Volatile fractions: These constitute 90-95% of the oil. These include monoterpenes and sesquiterpenes as well as their oxygenated derivatives along with aliphatic aldehydes, alcohols and esters. Nonvolatile residues: These comprise 1-10% of the oil. These include hydrocarbons, fatty acids, sterols, carotenoids, waxes and flavonoids. Major volatile constituents are hydrocarbons (e.g. pinene, limonene, bisabolene), alcohols (e.g. linalol, santalol), acids (e.g. benzoic acid, geranic acid), aldehydes (e.g. citral), cyclic aldehydes (e.g. cuminal), ketones (e.g. camphor), lactones (e.g. bergaptene), phenols (e.g. eugenol), phenolic ethers (e.g. anethole), oxides (e.g. 1,8 cineole) and esters (e.g. geranyl acetate). Essential oil components can also be subdivided into two distinct groups of chemical constituents: hydrocarbons which are made up almost exclusively of terpenes (monoterpenes, sesquiterpenes, and diterpenes) and oxygenated compounds which are mainly esters, aldehydes, ketones, alcohols, phenols and oxides (Table 2). Table 2. Major chemical components of plant derived essential oils. Plant species Main components Reference Commiphora molmol Lindestrene, furanoeudesma-1,3-diene, Furanoeudesma-1,4-diene-6-one [16] Tagetes minuta β-Phelandrene, Limonene, β-Ocimene, Dihydrotagetone, Tagetone, cis-Tagetenone, trans-Tagetenone [17] Cinnamomum zeylanicum δ-Cadinene, γ-Cadinene, β-Caryophyllene [18] Commiphora guidottii (E)-β-Ocimene [19] Boswellia rivae Limonene [19] Boswellia pirotta trans-Verbenol,Terpinen-4-ol [19] Boswellia neglecta α-Thujene, α-Pinene, Terpinen-4-ol [19] Canarium luzonicum α-Amyrin, β-Amyrin [20] Commiphora africana Bisabolol, β-Sesquiphellandrene, α-Oxobisabolene, γ-Bisabolene [21, 22] Protium pilosum α-Pinene, p-Cymene, α-Phellandrene [23] Commiphora myrrha Isofuranogermacrene, Lindestrene, Furanoeudesma-1,3-diene, Furanodiene, Curzerene, Germacrone [19, 24, 25] Protium heptaphyllum Terpinolene, β-Elemene, β-Caryophyllene, α-Pinene, Limonene, α-Phellandrene, β-Elemene [23, 26, 27] Ocimum basilicum 1,8-Cineole, Linalool, Estragole, α-Terpineol, α-Bergamotene [28] Laurus nobilis 1,8-Cineole, Linalool, α-Terpinyl acetate, Methyl eugenol, Eugenol [28] Coriandrum sativum Linalool, Geraniol, α-Pinene [28] Myristica fragrans Sabinene, α-Pinene, β-Pinene, Terpinen-4-ol, Safrole [28] Piper nigrum Caryophyllene, Sabinene, Limonene, Germacrene B, α-Pinene, α-Humulene [28] Mentha piperita Neomenthol, Isomenthone, 1,8-Cineole, Menth-8-ene, Neoisomenthol [28] Marjorana hortensis Terpinen-4-ol, γ-Terpinene, α-Terpinene, Sabinene, α-Terpineol [28] Foeniculum vulgare trans-Anethole, Fenchone, Estragole, [28] Canarium album β-Pinene, α-Terpinene, γ-Terpinene, Terpinen-4-ol [29] Chaubey Essential oils as green pesticides of stored grain insects 207 European Journal of Biological Research 2019; 9(4): 202-244 Plant species Main components Reference Thymus vulgaris α-Pinene, p-Cymene, Limonene, γ-Terpinene, cis-Sabinene hydrate, Linalool, Terpinen-4-ol [30] Salvia officinalis Camphor, 1,8-Cineole, α-Pinene, β-Pinene Camphene, α-Terpinyl acetate [30] Syzygium aromaticum Eugenol, β-Caryophyllene, α-Humulene [30] Rosmarinus officinalis α-Pinene, Camphene, 1,8-Cineole, Camphor [30] Cuminum cyminum β-Pinene, p-Cymene, γ-Terpinene, Cuminal, 2-Caren-10-al [30] Origanum vulgare Carvacrol, p-Cymene, Terpinolene [30] Artemisia haussknechtii Camphor, 1,8-Cineole, cis-Davanone, 4-Terpineol, Linalool, β-Fenchyl alcohol, Borneol [31] Laurus nobilis 1.8-Cineole, Sabinene, α-Terpinyl acetate, α-Pinene, α-Phellandrene, trans-b-Osimen [32] Boswellia carterii Isoincensole, Verticilla-4(20),7,11-triene, Isoincensole acetate [33] Boswellia papyrifera Isoincensole, Isoincensole acetate, n-Octanol, n-Octyl acetate [33] Bursera graveolens Limonene, α-Terpineol [34] Bursera simaruba Limonene, β-Caryophyllene, α-Humulene, Germacrene [35] Boswellia serrata Isoincensole, Isoincensole acetate, α-Thujene, α-Pinene, α-Thujene [33, 36-38] Trachyspermum ammi Thymol, γ-Terpinene, p-Cymene, β-Pinene [39] Dacryodes edulis Sabinene, Terpinene-4-ol, α-Pinene, p-Cymene, Myrcene, β-Caryophyllene, α-Thujene, α-Phellandrene, β-Pinene, [40-42] Boswellia sacra E-β-Ocimene, Limonene, E-Caryophyllene [43] Boswellia ameero (E)-2,3-Epoxycarene, 1,5-Isopropyl-2-methylbicyclo[3.1.0]hex-3-en-2- ol, α-Cymene, (3E,5E)-2,6-dimethyl-1,3,5,7-octatetraene, 1-(2,4-Dimethylphenyl) ethanol, 3,4-Dimethylstyrene, α-Campholenal, α-Terpineol [44] Coriandrum sativum Linalool, trans-Anethol, c-Terpinene, Geranyl acetate [45] Artemisia absinthium β-Pinene, β-Thujone [46] Fragaria vesca Myrtenol, Citronellol, Linalool, Nonanal [47] Bursera microphylla Caryophyllene, Myrcene [48] Commiphora habessinica β-Elemene, α-Selinene, Cadina-1,4-diene, Germacrene B, α-Copaene, t-Muurolol, Caryophyllene oxide, α-Cadinol [49] Bunium persicum p-Cuminaldehyde, γ-Terpinen-7-al, p-Cymene, γ-Terpinene [50] Cryptomeria japonica Α-Terpinene, γ-Terpinene, p-Cymine, 3-Carene, Terpinolene, β-Myrcene [51] Cinnamomum aromaticum Cis-Cinnamaldehyde, Eugenol, α-Cadinol, Caryophyllene, Ledol [52] Haplopappus foliosus Limonene, Bornyl acetate, Terpineol, p-Cymene, Agarospirol, α-Muurolene, δ-Cadinine, Caryophyllene [53] Thymus vulgaris p-Cymene, γ-Terpinene, Thymol, Carvacrol, E-β-Caryophyllene, Germacrene D, β-Bisabolene [54] Santiria trimera α-Humulene, β-Caryophyllene, α-Pinene, α-Terpineol, α-Pinene, β-Pinene [55, 56] Canarium schweinfurthii Octyl acetate, Nerolidol, p-Cymene, Limonene, α-Terpineol [57] Artemisia gorgonum Camphor, Chrysanthenone, Lavandulyl-Z-methylbutanoate, α-Phellandrene, Camphene, p-Cymene [58] Bahia ambrosoides Lomonene, α-Pinene, Germacrene D, Sabinene, δ-Thujene, γ-Curcumene, α-Bergamotene [53] Carum carvi (R)-Carvone, D-Limonene, α-Pinene, cis-Carveol [59] Cuminum cyminum Caryophyllene oxide, α-Pinene, Geranyl acetate, α-Caryophyllene [60] Prangos acaulis δ-3-Carene, α-Terpinolene, α-Pinene, Limonene [61] Foeniculum vulare Methyl chavicol, α-Phellandrene, Fenchone [62] Carum copticum Thymol, Terpinolene,o-Cymene [63] Zanthoxylum monophyllum Sabinene, 1,8-Cineole, cis-4-Thujanol [64] Chaubey Essential oils as green pesticides of stored grain insects 208 European Journal of Biological Research 2019; 9(4): 202-244 Plant species Main components Reference Zanthoxylum rhoifolium β-Myrcene, β- Phellandrene, Germacrene D [64] Zanthoxylum fagara Germacrene D-4-ol, Elemol, α-Cadinol [64] Artemisia annua Camphor, 1,8-Cineole, Linalool, β-Caryophyllene, (E)-β-Farnese, Germacrene D [64] Schinus molle α-Pinene, β-Pinene, Limonene, α-Ocimene, Germacrene D, γ-Cadinene, δ-Cadinene, Epi-bicyclosesquiphelandrene [65] Myristica fragrans α-Pinene, Sabinene, β-Pinene, Myrcene, Limonene, Terpine-4-ol, Safrole, Myristicin [66] Boswellia socotrana (E)-2,3-Epoxycarene, 1,5-Isopropyl-2-methylbicyclo[3.1.0]hex-3-en-2- ol, α-Cymene, (3E,5E)-2,6-dimethyl-1,3,5,7-octatetraene, 1-(2,4-Dimethylphenyl)ethanol,3,4-Dimethylstyrene, α-Campholenal, α-Terpineol, p-Cymene, 2-Hydroxy-5-methoxyacetophenone, Camphor [44, 67] Ammi visnaga Isobutyrate, 2,2-Dimethylbutanoic acid, Croweacin, Linalool [68] Angelica dahurica 3-Carene, β-Elemene, β-Terpinene, β-Myrcene [69] Eucalyptus bicostata, E. cinerea, E. maidenii, E. odorata, E. sideroxylon, E. astringens, E. lahmannii α-Pinene, p-Cymene 1.8-Cineole, Limonene, β-Eudesmol, α-Eudesmol, α-Terpineol, Pinocarveol, γ-Terpinene, Globulol [70] Smyrnium rotundifolium Myrcene, Furanodiene, Germacrone, α-Selinene [71] Artemesia judaica Piperitone, Camphor, Ethyl-cinnamate [72] Cupressus sempervirens α-Pinene, δ-3-Carene, Limonene, α-Terpinolene [73] Angelica sylvestris β-Phellandrene, α-Pinene, Myrcene, Germacrene D [71] Apium graveolens (Z)-3-Butylidenephthalide, 3-Butyl-4,5-dihydrophthalide, α-Thujene [74] Azorella cryptantha α-Pinene, α-Thujene, Sabinene, δ-Cadinene [75] Thamnosciadium junceum Limonene,, cis-Ocimene, Terpinolene, trans-Isomirticisin [71] Protium icicariba p-Cymene, α-Pinene, α-Terpinolene, Limonene, α-Copaene, γ-Elemene, δ-Cadinene [76] Cedrelopsis grevei (E)-β-Farnesene, δ-Cadinene, α-Copaene, β-Elemene, [77] Pimpinella anisum Camphène, Limonene, Fenchone, 4-Allylanisole, Anethole [78] Azadirachta indica β-Elemene, γ- Elemene, Germacrene D, β-Caryophyllene, Bicyclogermacrene, Pentacosane, Tetracosane, β-Germacrene, Dodecene octadecanol, Verdiflorol, Farnesol, α–Terpineol [79] Protium crassipetalum α-Copaene, Spathulenol, trans-Caryophyllene [76] Aucoumea klaineana α-Pinene, β-Pinene, α-Phellandrene, β-Phellandrene, p-Cymene, 1,8-Cineole, p-Acetyl anisole, 3-Carene, p-Cymene, Limonene, Terpinolene, Terpineol, 3-Carene, α-Terpineol, Eucalyptol [57, 80] Schinus terebinthifolius δ-3-Carene, Limonene, α-Phellandrene, α-Pinene [81] Parthenium ysterophorus Germacrene-D, trans-β-Ocimene, β-Myrcene [82] Ambrosia polystachya Germacrene-D, trans-β-Ocimene, β-Caryophyllene [82] Inula viscose E-Foreseen Epoxide, Nerolidol B [83] Pelargonium graveolens Citronellol, Geraniol, Caryophyllene oxide, Menthone, Linalool, β-Bourbonene, Iso-Menthone, Geranyl formate [84] Melissa officinalis Neral, Geranial, Citronellal [85] Origanum vulgare Thymol, γ-Terpinene, Carvacrol, Carvacrol methyl ether, cis-α-Bisabolene, Eucalyptol, p-Cymene, Elemol [86] Ruta graveolens 2-Nonanone, Undecanal, 2-Acetoxydodecane, 2-Decanone [87] Tithonia diversifolia α-Pinene,(E,E)-α-Farnesene, β-Caryophyllene [88] Houttuynia cordata α-Myrcene, 2-Undecanone, (Z)-β-Ocimene [88] Asarum glabrum Safrole, Apiole [88] Hedychium forrestii β-Pinene, β-Linalool, 1,8-Cineole, 4-Terpineol [89] Chaubey Essential oils as green pesticides of stored grain insects 209 European Journal of Biological Research 2019; 9(4): 202-244 Terpenes: Majority of essential oil components are terpenes. These contain hydrogen and carbon only. These are made of one or more 5-C unit, isoprene. These are classified into hemiterpenes (C5), monoterpenes (C10), sesquiterpenes (C15), diterpenes (C20), triterpenes (C30) and tetraterpenes (C40). These hydrocarbons may be acyclic, alicyclic (monocyclic, bicyclic or tricyclic) or aromatic. CH2 C CH CH3 CH3 Isoperene unit The monoterpenes (C10) are formed by coupling of two isoprene units (C5). They are the most representative molecules constituting 90% of essential oils. These have a great variety of structures. Limonene, myrcene, p-menthane, sabinene, cymene, phellandrene, thujane, fenchane, farnesene, azulene and cadinene are examples of this family (Fig. 1). Limonene Myrcene Menthane Sabinene Cymene Azulene α-Phellandrene β-Phellandrene α-Pinene β-Pinene Farnesene Cadinene α-Terpinene β-Terpinene γ-Terpinene δ-Terpinene α-Thujene β-Thujene Sabinene Germacrene A Germacrene B Germacrene C Germacrene D Germacrene E α-Terpinolene β-Elemene Camphene Ocemene γ-Terpinene Bisabolene Thujane Longifolene Copaene Fenchene 2-Carene 3-Carene Sesquiphellandrene Curcumene Figure 1. Common terpenes of essential oils. Esters: These are sweet smelling and give a pleasant smell to the oils. These are formed by reaction of alcohol with acid. Esters are very common and are found in a large number of essential oils. These include Chaubey Essential oils as green pesticides of stored grain insects 210 European Journal of Biological Research 2019; 9(4): 202-244 linalyl acetate, geraniol acetate, eugenol acetate, bornyl acetate, citronellyl acetate, neryl acetate etc (Fig. 2). Oxides: Oxides or cyclic ethers are the strongest odorants. The well known oxide is 1,8-cineole as it is the most omnipresent constituent in essential oils. Other examples of oxides are bisabolone oxide, linalool oxide, sclareol oxide, ascaridole, caryophyllene oxide, cis-piperitone oxide, aromadendrene oxide and bisabolene oxide (Fig. 3). Linalyl acetate Geraniol acetate Eugenol acetate Bornyl acetate cis-Chrysanthenyl acetate Citronellyl acetate Neryl acetate Figure 2. Common esters of essential oils. 1,8-cineole Linalool oxide Sclareol oxide Piperitenone oxide Ascaridole cis-Piperitone oxide Aromadendrene oxide Bisabolene oxide Caryophyllene oxide Figure 3. Common oxides of essential oils. Lactones: These are of relatively high molecular weight components. Some common lactones are nepetalactone, bergaptene, costuslactone, dihydronepetalactone, alantolactone, citroptene and psoralen (Fig. 4). Nepetalactone Bergaptene Costuslactone Alantolactone Dihydronepetalactone Citroptene Psoralen Figure 4. Common lactones of essential oils. Alcohols: Linalol, menthol, borneol, santalol, nerol, citronellol, bisabolol, eucalyptol, trans-carveol, dihydrocarveol, α-cadinol, δ-cadoniol, τ-cadinol, elemeol, nerol and geraniol are common alcohols of Chaubey Essential oils as green pesticides of stored grain insects 211 European Journal of Biological Research 2019; 9(4): 202-244 essential oils (Fig. 5). Phenols: These oxygen containing molecules are responsible for fragrance of oil. These aromatic components are among the most reactive components and are often found as crystals at room temperature. The most common phenols are thymol, eugenol, carvacrol, cumic alcohol, α-terpineol, safrole, verbenol and chavicol (Fig. 6). Linalol Menthol Borneol Santalol Nerol Citronellol Bisabolol Geraniol Eucalyptol Trans-Carveol Dihydrocarveol α-Cadinol δ-Cadoniol τ-Cadinol Elemeol Nerol Figure 5. Common alcohols of essential oils. Thymol Eugenol Carvacrol Chavicol α -Terpineol Safrole Verbenol Cumic alcohol Figure 6. Common phenols of essential oils. Aldehydes: These are highly reactive and characterized by -CHO group. These are common essential oil components that are unstable and oxidize easily. Geranial, neral, myrtenal, cuminaldehyde, citronellal, cinnamaldehyde, benzaldehyde and citral are common aldehydes of essential oils (Fig. 7). Ketones: These are characterized by –C=O group. These are not very common in majority of essential oils. These are relatively stable molecules and are not important as fragrances or flavour substances. Carvone, menthone, pulegone, fenchone, camphor, jasmone, thujone, methyl nonyl ketone, pinocamphone and verbenone are common ketones of essential oils (Fig. 8). Chaubey Essential oils as green pesticides of stored grain insects 212 European Journal of Biological Research 2019; 9(4): 202-244 Geranial Neral Myrtenal Cuminaldehyde Citronellal Cinnamaldehyde Benzaldehyde Citral Figure 7. Common aldehydes of essential oils. Carvone Menthone Fenchone Verbenone Camphor Jasmone Thujone Methyl nonyl ketone Pinocamphone Pulegone Verbenone Davanone Figure 8. Common ketones of essential oils. Physical properties of essential oils: 1. Essential oils are volatile and liquid at room temperature. 2. They are colourless or slightly yellowish. 3. They are less dense than water (sassafras and clove oils are exceptions). 4. They are always rotational and with a high refractory index. 5. They are soluble in alcohol and other organic solvents such as acetone, ether or chloroform. 6. They are lipid soluble and not very soluble in water. 3. BIOLOGICAL ACTIVITIES OF ESSENTIAL OILS AS INSECTICIDES Conventional synthetic insecticides play important role in protecting stored grains from insect pest infestation in the 20th and 21st century. Use of these conventional insecticides is believed to be one of the major reasons for growth in agricultural productivity in the 20th century. However, more and more public concern all over the world about long-term health and environmental effects of uncontrolled and extensive use of synthetic insecticides increases. Many laboratory studies and clinical cases have shown that almost all the conventional synthetic insecticides have the potential to affect ecosystems adversely; and most of them have acute or chronic toxicity to humans or other non-target organisms. Keeping these problems in mind, there is an urgent demand to reduce use of conventional insecticides and develop alternatives with no or little harmful effects on the environment and with no toxicity to non-target organisms including human. From time immemorial with the beginning of human civilization, several plant parts have been used to protect stored Chaubey Essential oils as green pesticides of stored grain insects 213 European Journal of Biological Research 2019; 9(4): 202-244 grains from insect pests. Still several natural products such as nicotine from tobacco, pyrethrum from chrysanthemums, rotenone from Derris root, sabadilla from lilies, ryania from the ryania shrub, limonene from citrus peel and neem from the tropical neem tree have been used to protect grains from insect pest infestations in storage in several countries. In recent years, scientific communities have focussed attention towards volatile plant products as a replacement of the synthetic pesticides. Essential oils are secondary metabolic products in plants whose functions are other than nutritions. These oils have strong aromatic components that give a plant its distinctive odour and flavour [90]. Essential oils are complex mixtures of a large number of constituents in variable ratios [91]. Their components and qualities vary with geographical distribution, harvesting time, growing conditions and extraction method [92]. These oils are liquid at room temperature and can be easily transformed from a liquid to a gaseous state at room temperature or a slightly higher temperature without decomposing [90]. Essential oils are very interesting natural plant products and they possess various biological properties. The term ‘biological properties’ include all activities that these volatile compounds exert on other organisms whether microbes, plants or animals. Knowledge of these essential oil producing plants, their chemistry and their biological properties is of prime importance not only to enable them to be utilized as natural pest control agents and replace commercial synthetic pesticides but also to enable us to understand the nature of their toxicity to non- target animals. Botanical insecticides degrade rapidly in air and moisture and are readily broken down by detoxification enzymes. This is very important because rapid breakdown suggests less persistence in the environment and reduced risks to non-target organisms. Plant derived essential oils are generally considered broad-spectrum and safe for the environment because variety of compounds they contain quickly biodegrade in soil. Essential oils and their constituents are primarily lipophilic compounds that act as toxins, feeding deterrents, repellent, oviposition deterrents and even attractant to a wide variety of insect pests. Due to their volatility, essential oils have limited persistence under natural conditions. Recent findings suggest that plant derived volatiles are neurotoxic via octopaminergic mode of action [93]. Thus, these natural products are safe for human and other vertebrates due to lack of octopaminergic mode of nerve conduction. 3.1. Attractants Presence of volatile essential oils and its components in plants provides an important defense strategy to plants especially against herbivorous insect pests. These plant derived essential oils also play a crucial role in plant-plant interactions and serve as attractants for some insects like pollinators. Attraction of insects by essential oils and its components have been studied. Petroski and Hammack [94] have reported that cinnamaldehyde, cinnamyl alcohol, 4-methoxy-cinnamaldehyde, geranylacetone and aterpineol attract adult corn rootworm beetles, Diabrotica sp. The cis-jasmone alone or in combination with linalool and/or phenylacetaldehyde has been reported to attract lepidopteran adults [95]. Geraniol and eugenol are effective attractants and are used to lure Japanese beetle, Popillia japonica [96]. Similarly, methyl-eugenol has been used to lure oriental fruit fly, Dacus dorsalis [96]. These attracted insects can then be killed by physical and/or chemical means. Katerinopoulos et al. [97] have demonstrated that 1,8-cineole from Rosmarinus officinalis attract grape berry moth, Lobesia botrana and flower thrips, Frankliniella occidentalis. Eugenol is a strong deterrent for most insect species, although in a few cases it can be an attractant [98]. They can act as internal messengers and as defensive substances against herbivores or as volatiles directing not only natural enemies to these herbivores but also attracting pollinating insects to their hosts [99]. Besides, attractive essential oil and its components can be used as bait in attracting parasitoids and predators for controlling their host insect Chaubey Essential oils as green pesticides of stored grain insects 214 European Journal of Biological Research 2019; 9(4): 202-244 species in biological insect pest management programme. These essential oils/components are useful for monitoring of these agricultural insect pests. 3.2. Repellents Insect repellents are those substances that act locally or distally to deter insects. Several essential oils and their constituents are known to repel several insect species especially coleopterans (Table 3). Table 3. Essential oils with repellent activity. Plant species Insect species Reference Carum copticum Callosobruchus maculatus [114] Artemisia scoparia C. maculatus, T. castaneum, S. oryzae [115] Melalecuca alternifolia C. maculatus, S. oryzae [116] Cinnamomum zeylanicum C. maculatus, S. oryzae [116] Syzygium aromaticum C. maculatus, S. oryzae [116] Cymbopogon flexuosus C. maculatus, S. oryzae [116] Thymus vulgaris C. maculatus, S. oryzae [116] Eucalyptus globules C. maculatus, S. oryzae [116] Simmondsia chinensis C. maculatus, S. oryzae [116] Anethum graveolens T. castaneum [117, 118] Nigella sativa T. castaneum [117, 118] Trachyspermum ammi T. castaneum [117, 118] Carum copticum T. castaneum, C. maculatus [119] Perovskia abrotanoides T. castaneum [120] Myristica fragrance T. castaneum [121] Illicium verum T. castaneum [121] Achillea wilhelmsii Plodia interpunctella [122] Hyssopus officinalis P. interpunctella [122] Zhumeria majdae P. interpunctella [122] Drimys winteri T. castaneum [123] Laurelia sempervirens T. castaneum [123] Schinus molle Trogoderma granarium, T. castaneum, C. maculatus [124] Carum carvi Meligethes aeneus [125] Thymus vulgaris M. aeneus [125] Piper cubeba T. castaneum [126] Zingiber officinale T. castaneum [126] Mentha longifolia C. maculates [127] Thymus kotschyanus C. maculates [127] Citrus reticulate C. maculatus, P. interpunctella [128] Carum copticum Plutella xylostella, T. castaneum [129] Perovskia abrotanoides P. xylostella, T. castaneum [129] Artemisia judaica C. maculatus, P. interpunctella [72] Achillea wilhelmsii C. maculatus, P. interpunctella [72] Hyssopus officinalis C. maculatus, P. interpunctella [72] Chaubey Essential oils as green pesticides of stored grain insects 215 European Journal of Biological Research 2019; 9(4): 202-244 Plant species Insect species Reference Zhumeria majdae C. maculatus, P. interpunctella [72] Piper cubeba T. castaneum, S. oryzae [130] Zingiber officinale T. castaneum, S. oryzae [130] Citrus aurantium T. castaneum [131] Cinnamomum zeylanicum T. castaneum [131] Gautheria fragrantissima T. castaneum [131] Lavandula officinalis T. castaneum [131] Oscimum sanctum T. castaneum [131] Anethum graveolens S. oryzae [132] Nigella sativa S. oryzae [132] Trachyspermum ammi S. oryzae [132] Citrus limonum Tenebrio molitor [133] Litsea cubeba T. molitor [133] Allium sativum S. oryzae [134] Cinnamomum tamala S. oryzae [134] Adhatoda vasica essential oil exhibited repellent activity against Sitophilus oryzae and Bruchus chinensis [100]. Ngoh et al. have investigated repellent activity of eugenol, isoeugenol, methyleugenol, safrole, isosafrole, α-pinene, limonene, 1,8-cineole and p-cymene against Periplaneta americana nymphs [101]. They proved that eugenol, methyl-eugenol, isoeugenol, safrole and isosafrole are better toxicants and repellents to insects than limonene, 1,8-cineole and p-cymene. Only α-pinene exhibited a considerable repellent effect on nymphs. Oils from Ocimum suave and Lippia repelled S. zeamais adults [102, 103]. Acorus calamus essential oil repelled Tribolium castaneum adults [31]. Essential oil from Jupinerus communis berries is a very good mosquito repellent [104]. Some essential oils repelled S. granarius and inhibited its feeding [105]. Absinthium essential oil exerted both toxic and repulsive effects on S. granarius [106]. Chahal et al. have reported that turmerone and dehydroturmerone, the major constituents of turmeric rhizome powder oil are strong repellents to stored grain pests [107]. Turmeric oil has been reported to provide protection to wheat grains against T. castaneum adults. Garcia et al. have shown repellent behaviour of Baccharis salicifolia essential oil against T. castaneum adults [108]. Essential oil isolated from Tagetes terniflora have been reported effective as repellent against fifth instar of T. castaneum [109]. Wang et al. have tested and established the repellent and fumigant activity of essential oil from Artemisia vulgaris against T. castaneum adults [110]. Repellent properties of Eucalyptus essential oil have also been well established. This oil presented high repellency against Ixodes ricinus, Aedes albopictus and Pediculus humanus capitis [111, 112]. Triaenops persicus oil has been reported for insecticidal activity against adults of T. castaneum and S. oryzae [90]. Garlic and mint essential oils have been evaluated against the cowpea aphid, Aphis craccivora and its absolute repellent activity was proved on adult aphids. Garlic oil had higher repellent than mint oil [113]. This repellent action of essential oils may be related to major constituents, e.g., piperitone, camphor and (E)-ethyl cinnnamate. Essential oils from Cuminum cyminum, Piper nigrum, Illicium verum, Myristica fragrans, Foeniculum vulgare, Trachyspermum ammi, A. graveolens and Nigella sativa have been isolated and its repellent activity have been determined against T. castaneum adults [117, 118, 121]. Repellent activity of essential oils from Afromomum melegueta seeds and Zingiber officinale rhizomes has been evaluated against R. dominica. Both Chaubey Essential oils as green pesticides of stored grain insects 216 European Journal of Biological Research 2019; 9(4): 202-244 oils repelled adult beetles [135]. Lopez et al. have reported that Coriandrum sativum oil is very toxic to S. oryzae, R. dominica and C. pusillus while, fractions of camphor are highly toxic to R. dominica and C. pusillus [75]. Cosimi et al. have tested essential oils from Laurus nobilis, Citrus bergamia and Lavandula hybrida for repellent activities against S. zeamais and Cryptolestes ferrugineus adults [136]. C. bergamia essential oil exerted the highest repellency on S. zeamais adults. Repellent active compounds isolated from Limnophila geoffrayi and Schizonepeta tenuifolia are pulegone, linalool, eugenol, thymol and methyl chavicol [137]. While, other repellent compounds such as α-pinene, β-pinene, D-limonene, (E)-3,7-dimethyl-2,6- octadienal have been isolated from Armoracia rusticana, Pimpinella anisum, Allium sativum, Laurelia sempervirens and Drimys winteri [123, 138]. Kheradmand et al. have evaluated and established repellent activity of jojoba, Simmondasia chinensis seed oil on Oryzaephilus surinamensis and C. maculatus [139]. Kim et al. have evaluated repellent activity of origanum essential oil and its nine constituents against T. castaneum adults [140]. Among the nine constituents of origanum oil, caryophyllene oxide and α-pinene produced strong repellency. Thymol, carvacrol and myrcene which are hydrogenated monoterpenoids, have also shown strong repellency. Moderate and low repellency has been produced by terpinene and camphene. Abdel-Sattar et al. have shown that essential oils of Schinus molle (fruit and leaf) have repellent activity against T. granarium and T. castaneum [124]. They identified p-cymene as a major component in fruits and leaf oils. The repellent activity of essential oil obtained from leaves induced higher activity than that of fruit. Zapata and Smagghe have shown that essential oils from leaves and bark of Laurelia sempervirens and Drimys winteri have highly repellent activity against T. castaneum [123]. Liu et al. have reported contact toxicity of Artemisia capillaris and A. mongolica essential oils against S. zeamais [141]. Insecticidal activity may be due to main components, 1,8-cineole, germacrene D, α-pinene, germacrene D and γ-terpinene of A. mongolic essential oil. Pavela has evaluated ten essential oils for their repellent activity against Meligethes aeneus [125]. Oils isolated from Carum carvi and Thymus vulgaris have shown the highest repellent activity. Chaubey has evaluated Z. officinale and Piper cubeba essential oils for its repellent against T. castaneum [126]. Z. officinale and P. cubeba essential oils have repelled adults of T. castaneum significantly even at very low concentrations. Repellent activity of essential oils obtained from Mentha longifolia and Thymus kotschyanus has been evaluated against C. maculatus [127]. Ajayi and Olonisakin have studied and established repellent activities of Syzgium aromaticum, Piper guineense and Xylopia aethiopica essential oils against T. castaneum [142]. Origanum vulgare and Thymus vulgaris essential oils have been tested against Nezara viridula [143]. Khani and Asghari have evaluated and established insecticidal activity of Pulicaria gnaphalodes essential oil against T. confusum and C. maculatus [144]. Ben Jemba et al. have reported Laurus nobilis essential oils from Tunisia, Algeria and Morocco for their repellent and toxic activities against R. dominica and T. castaneum. Artemisia judaica essential oil has been reported specific against cowpea weevil, C. maculatus [145]. A. judaica essential oil has been reported for insecticidal activity against C. maculatus [72]. Their toxic effect has been attributed to piperitone, camphor and (E)-ethyl cinnnamate. These compounds are monoterpenoids and lipophilic. These have fast penetration properties into insects which consequently interfere with biochemical and physiological functions [146]. Abd-Elhady has reported A. judaica essential oil for its repellent activity against cowpea weevil, C. maculatus [72]. It reduced egg laying in C. maculatus. Essential oil of A. sativum has been isolated and evaluated for its repellent activities against T. castaneum and S. oryzae. A. sativum essential oil repelled T. castaneum and S. oryzae adults at very low concentration [134, 147]. Essential oils from Citrus limonum and Litsea cubeba have been reported for repellent activity against adults of Tenebrio molitor [133]. Repellent activity of these essential oils may be due to the presence of D-limonene and 3,7-dimethyl-6-octenal in C. limonum essential oil and Chaubey Essential oils as green pesticides of stored grain insects 217 European Journal of Biological Research 2019; 9(4): 202-244 (E)-3,7-dimethyl-2,6-octadienal and (E)-cinnamaldehyde in L. cubeba. 3.3. Antifeedants Antifeedants may be defined as substances that deter from feeding when come in contact made with insects. Plant derived essential oils and its compounds have been known to exhibit antifeedant properties against a number of insect pest species (Table 4). Paruch et al. have reported a terpenoid lactone exhibiting antifeeding activity against S. granarium, T. granarium and T. confusum [148]. Oils isolated from Curcuma longa and Z. officinale have been found effective as antifeedant and insect growth regulators [149]. Antifeedant activity of 1,8-cineole has been demonstrated against T. castaneum [150]. Tripathi et al. have reported feeding deterrence activity of C. longa leaf essential oil against adult and larvae of R. domestica, S. oryzae and T. castaneum which has been attributed to the presence of monoterpenes, carvone and dihydrocarvone [151]. Table 4. Essential oils with antifeedant activity. Plant species Insect species Reference Piper cubeba T. castaneum, S.oryzae [132] Zingiber officinale T. castaneum, S.oryzae [132] Allium sativum S. oryzae [134] Cinnamomum tamala S. oryzae [134] Curcuma longa R. dominica, S. oryzae, T. castaneum [151] Schinus molle S. oryzae [156] Eucalyptus globulus T. castaneum [157] Lavandula stoechas T. castaneum [157] Tripathi et al. have evaluated repellent and antifeedant activities of Curcuma leaf oil and d-limonene on R. dominina, S. oryzae and T. castaneum. Huamg and Ho established antifeedant activity of cinnamaldehyde against T. castaneum and S. zeamais [151, 153]. Perillyl alcohol, cisverbenol, cis-carveol, geraniol, citronellal, perillaldehyde, caryophyllene oxide, carvacrol, 4-isopropylbenzenemethanol, thymol, 3-carene and myrcene have been reported the most effective repelling chemicals. The toxicity of essential oil of Piper aduncum has been tested against Cerotoma tingomarianus. This oil causes physiological problems and reduces foliar consumption by beetles [154]. Rana and Rashmi have shown antifeedant activity of Vitex negundo essential oil against C. chinensis and S. oryzae [155]. Benzi et al. have evaluated nutritional indices and feeding deterrent activities of essential oil from leaves and fruits of the Brazilian pepper tree, Schinus molle on S. oryzae adults [156]. Oils from both plant parts have been found to alter nutritional indices. Fruit essential oil has a strong feeding deterrent activity while leaf oil has a slight effect. Ebdadollahi [157] has studied antifeedant activity of Eucalyptus globulus and Lavandula stoechas essential oils against T. castaneum. All the tested essential oils cause reductions in feeding of insects. Chaubey has evaluated antifeeding activities of essential oils from Zingiber officinale rhizomes and Piper cubeba berries as well as pure compounds, α-pinene and β-caryophyllene against T. castaneum and S. oryzae [132]. β-Caryophyllene has been shown highest toxicity followed by P. cubeba, Z. officinale and α-pinene against both insects. S. oryzae is more sensitive than T. castaneum to both essential oils and pure compounds. Feeding deterrency is maximum in both insects by P. cubeba essential oil followed by Z. officinale essential oil, β-caryophyllene and α-pinene. Allium sativum essential oil exhibits antifeedant activities against T. castaneum and S. oryzae Chaubey Essential oils as green pesticides of stored grain insects 218 European Journal of Biological Research 2019; 9(4): 202-244 [134, 147]. The antifeedant activity of essential oils can be due to its major constituents. Moreover, the minor constituents of essential oils play an important role in changing the activity by synergistic effects. In general, the mixture of chemical constituents is more effective than that of individual pure compounds. Therefore, synergistic effects between essential oils components are playing an essential role in essential oils activity [158]. Exploration of the influence of chemical complexity of essential oils on feeding behaviour of insects can help in the development of new crop protection products for use in integrated pest management. However, all the products need to be tested for their effects on non-target organisms and their environmental impact and future. Understanding the role of each constituent in the efficacy of oil provides an opportunity to create artificial blends of different constituents on the basis of their activity and efficacy against different pests. 3.4. Ovicidal and oviposition deterrants Essential oils are not only active against adults and larvae but also inhibit reproduction and egg hatching (Table 5). This action could be the result of female sensitivity resulting in reduction in fecundity. The inhibition of reproduction of Acanthoscelides obtectus by essential oils belonging to Labiatae, Umbelliferae, Lauraceae, Myristicaceae, Graminae, Rutacae, Myrtacae families has been observed. This beetle has been shown to be a convenient model to point out with accuracy which reproductive stage is targeted and speed of the activity of essential oils [159]. Table 5. Essential oils with ovicidal activity. Plant species Insect species Reference Allium sativum T. castaneum [166] Myristica fragrance T. castaneum [167] Cuminum cyminum T. confusum [168] Cuminum cyminum E. kuehniella [168] Pimpinella anisum T. confusum [168] Pimpinella anisum E. kuehniella [168] Ammi visnaga Mayetiola destructor [169] Carum carvi Trialeurodes vaporariorum [170] Anethum graveolens C. chinensis [163] Cuminum cyminum C. chinensis [163] Illicium verum C. chinensis [163] Myristica fragrans C. chinensis [163] Nigella sativa C. chinensis [163] Piper nigrum C. chinensis [163] Trachyspermum ammi C. chinensis [163] Elletaria cardamomum T. castaneum [171] Cinnamomum zeylanicum T. castaneum [171] Syzygium aromaticum T. castaneum [171] Eucalyptus spp. T. castaneum [171] Azadirecta indica T. castaneum [171] Piper cubeba C. chinensis [147] Zingiber officinale C. chinensis [147] Allium sativum C. chinensis [172] Chaubey Essential oils as green pesticides of stored grain insects 219 European Journal of Biological Research 2019; 9(4): 202-244 Citrus peel oil causes a high reduction in oviposition of C. maculatus [158, 160]. Acorus calamus oil reduces oviposition in C. maculatus [161]. Carvone completely suppresses egg hatching of T. castaneum [151]. Brito et al. have studied the effects of Eucalyptus citriodora, E. globulus and E. staigerana essential oils on oviposition and number of emerged insects of Zabrotes subfasciatus and C. maculatus [162]. These essential oils reduce percentage of viable eggs and emerged insects of both coleopterous species. A. graveolens, C. cyminum, I. verum, M. fragrans, N. sativa, P. nigrum and T. ammi oils have been evaluated for oviposition inhibitory activities against C. chinensis. These essential oils reduce oviposition potential of the insect when fumigated with sublethal concentrations [163]. Waliwitiya et al. have evaluated and established oviposition deterrent activities of eugenol, citronellal, thymol, pulegone and cymene. [164] Nondenot et al. have tested essential oils of Ageratum conyzoides, Citrus aurantifolia and Melaleuca quinquenervia on C. maculatus [165]. These oils show insecticidal activity and reduce egg lying capacity in C. maculatus. Ajayi and Olonisakin have been evaluated ovicidal activity of Syzgium aromaticum, Piper guineense and Xylopia aethiopica essential oils against T. castaneum [142]. The three essential oils are able to reduce progeny emergence of T. castaneum. Higher number of adults emerged in X. aethiopica than in S. aromaticum and Piper guineense. Chaubey has shown oviposition inhibitory activity of α-pinene and β-caryophylene alone or in binary combination against T. castaneum by fumigation method [132]. Fumigation of T. castaneum adults with sublethal concentrations of α-pinene, β-caryophyllene and its binary combination reduce oviposition potential of insect. This study indicates that α-pinene and β-caryophylene in binary combination show synergism and reduce egg laying capacity in T. castaneum. A. sativum essential oil has been evaluated for oviposition inhibitory activities against S. oryzae. Exposure of S. oryzae adults to sublethal concentrations of A. sativum oil inhibits oviposition [134]. In all cases, essential oils and their components have strong effects on egg, oviposition and egg hatching of insect pests. Essential oils have been reported to have low vapour density than fatty oils; hence, they are readily volatilized. This could be the reason why most of the eggs that might have hatched could not survive the volatility effects of the essential oils especially as the concentration/dosage of oils increased. Results clearly indicate variations in the activity of essential oils regarding the stage of the insect, species of insect and plant origin of essential oil. 3.5. Toxicants Several essential oils and their components have been evaluated for their toxic nature against diverse group of insect pests, and most of them have shown promising toxicity either by its fumigant or by contact action [117, 118, 121, 123, 124, 126, 130, 132, 134, 147, 151, 173-175] (Table 6). Table 6. Essential oils toxic to stored grain insect pests. Plant species Insecticidal activity and tested insect Reference Anethum sowa Fumigant activity against T. castaneum [181] Artemisia annua Fumigant activity against T. castaneum [182] Elletaria cardomum Fumigant activity against T. castaneum [184] Apium graveolens Fumigant toxicity against Acanthoscelides obtectus [192] Foeniculum vulare Fumigant toxicity against adults of T. castaneum [193] Pimpinella anisum Fumigant toxicity against adults of T. castaneum [193] Foeniculum vulare Contact and fumigant toxicity against adults of Lasioderma serricorne [194] Cnidium officinale Contact and fumigant toxicity against adults of L. serricorne [194] Foeniculum vulare Adulticidal on S. oryzae and C. chinensis [195] Chaubey Essential oils as green pesticides of stored grain insects 220 European Journal of Biological Research 2019; 9(4): 202-244 Plant species Insecticidal activity and tested insect Reference Angelica dahurica Contact and fumigant toxicity against adults of L. serricorne, S. oryzae and C. chinensis [194, 195] Carum copticum Contact and fumigant toxicity against S. oryzae and T. castaneum [196] Trachyspermum ammi Fumigant toxicity against T. castaneum [117] Anethum graveolens Fumigant toxicity against T. castaneum [117] Nigella sativa Fumigant toxicity against T. castaneum [117] Anethum graveolens Fumigant toxicity against C. chinensis [163] Cuminum cyminum Fumigant toxicity against adults of C. chinensis [163] Illicium verum Fumigant toxicity against adults of C. chinensis [163] Myristica frangrans Fumigant toxicity against adults of C. chinensis [163] Nigella sativa Fumigant toxicity against adults of C. chinensis [163] Piper nigrum Fumigant toxicity against adults of C. chinensis [163] Trachyspermum ammi Fumigant toxicity against adults of C. chinensis [163] Coriandrum sativum Fumigant toxicity against adults of S. oryzae, R. dominica and Cryptolestes pusillus [75] Coriandrum sativum Toxicity against adults of S. granarius [197] Heracleum persicum Fumigant toxicity on adults of C. maculatus [198] Prangos acaulis Adulticidal and larvicidal against C. maculatus [199] Cinnamomum zetlanicum Fumigant toxicity against C. maculatus, S. oryzae adults [116] Syzygium aromaticum Fumigant toxicity against C. maculatus, S. oryzae adults [116] Cymbopogon flexuosus Fumigant toxicity against C. maculatus, S. oryzae adults [116] Thymus vulgaris Fumigant toxicity against C. maculatus, S. oryzae adults [116] Eucalyptus globules Fumigant toxicity against C. maculatus, S. oryzae adults [116] Simmondsia chinensis Fumigant toxicity against C. maculatus, S. oryzae adults [116] Trachyspermum ammi Fumigant toxicity against adults of S. oryzae [200] Piper nigrum Fumigant toxicity against adults of S. oryzae [200] Cuminum cyminum Fumigant toxicity against adults of S. oryzae [200] Azilia eryngioides Fumigant toxicity on adult of S. granarius and T. castaneum [201] Foeniculum vulare Fumigant toxicity against S. oryzae, S. granarius adults [202] Ostericum sieboldii Contact and fumigant toxicity against T. castaneum, S. zeamais adults [203] Cuminum cyminum Fumigant toxicity against C. maculatus adults [204] Coriandrum sativum Fumigant toxicity against T. confusum and C. maculatus adults [205] Coriander sativum Fumigant toxicity against C. maculatus, T. castaneum adults [205] Heracleum persicum Adulticidal against C. maculates [206] Citrus aurantium Fumigant toxicity against T. castaneum adults [131] Cinnamomum zeylanicum Fumigant toxicity against T. castaneum adults [131] Gautheria fragrantissima Fumigant toxicity against T. castaneum adults [131] Lavandula officinalis Fumigant toxicity against T. castaneum adults [131] Oscimum sanctum Fumigant toxicity against T. castaneum adults [131] Trachyspermum ammi Fumigant toxicity against adults of S. oryzae [132] Anethum graveolens Fumigant toxicity against adults of S. oryzae [132] Nigella sativa Fumigant toxicity against adults of S. oryzae [132] Piper cubeba Fumigant toxicity against adults of S. oryzae, T. castaneum [132] Chaubey Essential oils as green pesticides of stored grain insects 221 European Journal of Biological Research 2019; 9(4): 202-244 Plant species Insecticidal activity and tested insect Reference Zingiber officinale Fumigant toxicity against adults of S. oryzae, T. castaneum [132] Syzygium aromaticum Fumigant toxicity against S. oryzae, Acanthoscelides obtectus adults [207] Citrus reticulate Fumigant toxicity against T. castaneum adults and larvae [208] Citrus sinensis Fumigant toxicity against T. castaneum adults and larvae [208] Eucalyptus amaldulensis Fumigant toxicity against S. oryzae adults [189] E. grandis Fumigant toxicity against S. oryzae adults [189] E. viminalis Fumigant toxicity against S. oryzae adults [189] E. microtheca Fumigant toxicity against S. oryzae adults [189] E. sargentii Fumigant toxicity against S. oryzae adults [189] Datura stramonium Fumigant toxicity against T. castaneum, Trogoderma granarium, Cryptolestes ferrugineus adults [209] Eucalyptus camaldulensis Fumigant toxicity against T. castaneum, T. granarium, C. ferrugineus adults [209] Moringa oleifera Fumigant toxicity against T. castaneum, T. granarium, C. ferrugineus adults [209] Nigella sativa Fumigant toxicity against T. castaneum, T. granarium, C. ferrugineus adults [209] Citrus limonum Fumigant toxicity against Tenebrio molitor adults [133] Cymbopogon citrates Fumigant toxicity against T. molitor adults [133] Litsea cubeba Fumigant toxicity against T. molitor adults [133] Muristica fragrans Fumigant toxicity against T. molitor adults [133] Allium sativa Fumigant toxicity against S. oryzae adults [134] Cinnamomum tamala Fumigant toxicity against S. oryzae adults [210] Gaultheria and Eucalyptus oils exhibit high toxicity on S. oryzae and C. chinensis [176]. Pulegone, linalool and limonene are known to cause fumigant toxicity against rice weevil, S. oryzae. Mentha citrata oil containing linalool and linalyl acetate exhibit significant fumigant toxicity to rice weevils [177]. Insects like S. zeamais, T. castaneum and Prostephanus truncates are very sensitive to topical applications of Citrus oil [178]. Solidago canadensis oil shows strong toxic action against S. granarius [179]. Eugenol is also toxic to S. granaries [180]. Essential oils of Anethum sowa, Artemisia annua, Lippia alba and Elletaria cardomum have been reported for their toxic behaviour against T. castaneum [181-184]. Carvone and menthol are the most effective as fumigant against T. castaneum and C. maculatus. Cineole exhibits both contact and fumigant toxicity against T. castaneum [150]. Lee et al. have reported toxicity of menthol, methonene, limonene, α-pipene, β-pipene and linalool against S. oryzae and proved that these oil components exert its toxicity by inhibiting acetylcholine esterase enzyme [185]. Trans-anethole, thymol, 1,8-cineole, carvacrol, terpineol and linalool have been evaluated as fumigants against T. castaneum but only trans-anethole shows significant effect [186]. Essential oils from seeds of Coriandrum sativum and Carum carvi have been evaluated for fumigant toxicity against S. oryzae, R. dominica and Cryptolestes pusillus. Coriander contains linalool as the main component and is active against the three pests. Camphor-rich fractions are very toxic to R. dominica and C. pusillus. Carvone is the most effective monoterpenoid against S. oryzae. (E)-Anethole is toxic to R. dominica while vapours of limonene kills adults of C. pusillus [75]. A comparative study has been conducted to assess contact and fumigant toxicities of monoterpenes viz. camphene, camphor, carvone, 1-8-cineole, cuminaldehyde, fenchone, geraniol, limonene, linalool, menthol and myrcene on S. oryzae and T. castaneum. In fumigant toxicity assays, 1-8-cineole has been found most effective against S. oryzae and T. castaneum. Structure-toxicity investigations reveal that carvone has the highest contact toxicity against both Chaubey Essential oils as green pesticides of stored grain insects 222 European Journal of Biological Research 2019; 9(4): 202-244 insects. In vitro inhibition studies of acetylcholine esterase from adults of S. oryzae show that cuminaldehyde inhibits enzyme activity most effectively followed by 1-8-cineole, limonene and fenchone. 1-8-Cineole is the most potent inhibitor of acetylcholine esterase activity from T castaneum larvae followed by carvone and limonene [187]. Essential oils of tea tree (Melaleuca alternifolia), cinnamon (Cinnamomum zeylanicum), cloves (Syzygium aromaticum), lemongrass (Cymbopogon flexuosus), thyme (Thymus vulgaris), eucalyptus (Eucalyptus globulus), and jojoba (Simmondsia chinensis) have been tested for their fumigant activity against C. maculatus and S. oryzae adults. Mortality increases with increasing concentration of oils and exposure period. The effect of volatile compounds of Citrus reticulata and C. sinensis oils have been studied on T. castaneum and indicated that essential oil of C. reticulata shows more toxic effects than that of C. sinensis against larvae and adult of T. castaneum [188]. Fumigant toxicity of essential oils from five species of Eucalyptus viz. E. camaldulensis, E. grandis, E. viminalis, E. microtheca and E. sargentii have been studied against S. oryzae adults [189]. Results have indicated that mortality in adults increases with increasing concentration and exposure time. Insecticidal activity of essential oils from Datura stramonium, Eucalyptus camaldulensis, Moringa oleifera and Nigella sativa against three major insect pest viz., T. castaneum, T. granarium and C. ferrugineus has been determined [190]. Essential oils fumigation causes mortality at all levels of concentration and exposure periods tested. D. stramonium oil is found to be the most toxic against T. granarium and C. ferrugineus while N. sativa shows the highest fumigant mortality against T. castaneum. Essential oils naturally are liquid at room temperature and get easy to change to vapours at room or with slightly higher temperature without any decomposition [90]. Therefore, volatile oils are frequently used as a fumigant against insects of stored grain. The mechanism of toxicity of essential oils and its constituents may be due to their neurotoxic effect. Essential oil and their active compound thymol can interact with neuromodulator octopamine. They induce neurotoxicity via effects on gated chloride channels GABA. Thymol has been reported to induce high toxicity to some insects like S. oryzae [191]. 3.6. Growth inhibitors Many essential oils and its constituents have been investigated and established for their egg laying, growth inhibitory and progeny production inhibitory activities against different insect pests. 3.6.1. Progeny production inhibitors Fumigant toxicity of Cymbopogon flexuosus leaf oil has been investigated on progeny production of R. dominica, S. oryzae and T. castaneum. This oil shows high effectiveness against R. dominica and S. oryzae [211]. Similarly, essential oil from Clausena anisata and a mixture of it with clay have been investigated for its insecticidal activity and effects on progeny production. The aromatized clay powder as well as essential oil reduces the F1 progeny insect production [212]. The activity of Cymbopogon martini, Piper aduncum, P. hispidinervium, Melaleuca sp. and Lippia gracilis oils and fixed oils of Helianthus annuus, Sesamum indicum, Gossypium hirsutum, Glycine max and Caryocar brasiliense have been studied against C. maculatus. These oils except Melaleuca sp. reduce egg viability and adult emergence to approximately 100% [213]. C. cyminum, P. nigrum, F. vulgare, T. ammi, A. graveolens, I. verum, M. fragrans and N. sativa essential oils reduce egg hatching rate, pupation and adult emergence when fumigated with sublethal concentrations. The essential oil of N. sativa has been found most effective followed by A. graveolens, C. cyminum, I. verum, P. nigrum, M. fragrans and T. ammi oils [163]. Bachrouch et al. have tested fecundity and hatching rate of Ectomyelois ceratoniae and Ephestia kuehniella exposed to Pistacia lentiscus essential oil [214]. Fecundity and hatching rate of both insects decreases with increase in concentration or exposure time to oil. P. lentiscus Chaubey Essential oils as green pesticides of stored grain insects 223 European Journal of Biological Research 2019; 9(4): 202-244 oil is toxic to eggs of E. kuehniella and E. ceratoniae. Essential oils from rhizomes of Z. officinale and berries of P. cubeba have been evaluated for developmental inhibitory activities against T. castaneum. Fumigation with sublethal concentrations of these essential oils reduces oviposition potential of adults and inhibits development of larvae to pupae and the pupae to adults [126]. Essential oil of A. sativum has been evaluated for its oviposition inhibitory activities against T. castaneum. A. sativum reduces oviposition potential of adults when treated by fumigant and contact method both [147]. 3.6.2. Development inhibitors Several essential oils and their constituents have properties similar to juvenile hormone and act as insect growth regulators (Table 7). 1,8-Cineole isolated from Artemisia annua is also a potential insecticidal allelochemical that reduce growth rate, food consumption and food utilization in some post harvest pests [215, 216]. Essential oil from C. schoenanthus shows development inhibition in all stages of C. maculatus [217]. Essential oil from Hyptis spicigera has been evaluated for insecticidal activities on C. maculatus. Essential oil has dose-dependent insecticidal effect while sublethal doses are repellent to adults, reduces oviposition and eggs viability with increasing doses. Essential oil shows lethality in larvae developing within cowpea seeds; and younger instars are more susceptible [218]. The fumigant toxicity of Laurus nobilis and R. officinalis oils has been evaluated against all development stage of T. confusum. The major component of both oils is 1,8-cineole. The two oils are toxic to all stages of the insect [219]. C. cyminum, P. nigrum, F. vulgare, T. ammi, A. graveolens, I. verum, M. fragrans and N. sativa essential oils cause death of T. castaneum larvae and adults by fumigation. These essential oils reduce oviposition potential and increase developmental period of T. castaneum. Fumigation inhibits development of larvae to pupae and the pupae to adults and also result in the deformities in different developmental stages of insect [117, 118, 121]. They cause disruption in growth and affect reproduction of insects. M. fragrans, N. sativa, P. nigrum and T. ammi oils induce changes in growth and reproduction of C. chinensis [163]. Oviposition deterrence has been recorded when C. copticum and Vitex pseudo-negundo essential oils have been applied on C. maculatus [220]. Elettaria cardamomum oil has shown oviposition deterrence effect on C. maculatus. Therefore, treatment with this essential oil reduces numbers of insects in treated grain [221]. Table 7. Essential oils with insect growth regulatory (igr) activity. Plant species Insect species Reference Trachyspermum ammi T. castaneum [117] Anethum graveolens T. castaneum [118] Cuminum cyminum T. castaneum [118] Piper nigrum T. castaneum [118] Foeniculum vulgare T. castaneum [118] Carum copticum C. maculatus [220] Anethum graveolens C. chinensis [163] Cuminum cyminum C. chinensis [163] Illicium verum C. chinensis [163] Myristica fragrans C. chinensis [163] Nigella sativa C. chinensis [163] Piper nigrum C. chinensis [163] Trachyspermum ammi C. chinensis [163] Chaubey Essential oils as green pesticides of stored grain insects 224 European Journal of Biological Research 2019; 9(4): 202-244 Plant species Insect species Reference Ageratum conyzoides C. maculatus [224] Citrus aurantifolia C. maculatus [224] Melaleuca quinquenervia C. maculatus [224] Citrus paradise R. dominica [222] Citrus reticulate R. dominica [222] Zingiber officinale T. castaneum [132] Piper cubeba T. castaneum [132] Allium sativum T. castaneum [223] Developmental inhibitory activities of α-pinene and β-caryophyllene alone or in binary combination have been determined against 4th instars larvae of T. castaneum. Percentage of larvae transformed into pupae and percentage of pupae transformed into adult decreases when fumigated with sublethal concentrations of α-pinene and β-caryophyllene alone or in binary combination. Results indicate that α-pinene and β-caryophylene in binary combination show synergism and reduce pupation and adult emergence in T. castaneum [130]. Abbas et al. have reported C. reticulata oil inhibits growth and pupation in R. domonica [222]. Several essential oils are good inhibitors of pest’s oviposition disturbing general growth of the populations. Essential oil of A. sativum has been evaluated for its developmental inhibitory activities against T. castaneum. A. sativum essential oil interferes with developmental processes and reduces transformation of larvae into pupae and adult emergence [223]. This disruption in growth of insects may be due to inhibition of different biosynthetic processes of insects at different growth stages. These studies revealed good results for utilizing sublethal concentrations/doses of essential oils and its constituents in reducing egg lying and hatchability, progeny production and growth inhibition. 3.7. Mode of action of essential oils Several plant derived essential oils and its constituents have been described as insecticides [225]. Thus, the doses or concentrations of essential oils and its constituents needed to kill insect pests and their mechanism of actions are important for the safety of humans and other non-trget vertebrates. The toxicity of essential oils in insects appears to be the result of effects mainly on the insect's nervous system either by inhibition of acetylcholinesterase or by antagonism of the octopamine receptors [93]. The rapid action against some insects is indicative of a neurotoxic mode of action similar to that of conventional synthetic insecticides. Several studies indicate that essential oils and monoterpenoids cause insect mortality by inhibiting acetylcholinesterase enzyme activity. Ryan and Byrne have suggested that the toxic effect may be attributed to reversible competitive inhibition of acetylcholinesterase by binding to active site of the enzyme [226]. Chaubey has reported that A. sativum essential oil inhibits acetylcholinesterase enzyme activity in T. castaneum and S. oryzae adults [134, 210, 223]. A monoterpenoid, linalool has been demonstrated to act on the nervous system affecting ion transport and the release of acetylcholine esterase in insects [227]. Octopamine has a broad spectrum of biological roles in insects acting as a neurotransmitter, neurohormone and circulating neurohormone-neuromodulator [228, 229]. Octopamine exerts its effects through interaction with at least two classes of receptors. On the basis of pharmacological effects, these have been designated as octopamine-1 and octopamine-2 [230]. Interruption in the functioning of octopamine results in total break down of nervous system in insects. Therefore, octopaminergic system of insects represents a target for insect control. The lack of octopamine receptors in vertebrates accounts for the mammalian selectivity of essential Chaubey Essential oils as green pesticides of stored grain insects 225 European Journal of Biological Research 2019; 9(4): 202-244 oils as insecticides. A number of essential oil compounds have been demonstrated to act on octopaminergic system of insects [231]. Enan has suggested that toxicity of essential oil/constituents is related to the octopaminergic nervous system of insects [232]. Kostyukovsky et al. have shown the activity of two essential oil constituents, ZP-51 and SEM-76 on several insect species [93]. Both ZP-51 and SEM-76 show an inhibitory action on acetylcholinesterase, but only at the high dose. Essential oils can also disrupt communication in mating behaviour of insect by blocking the function of antennal sensilla. This lowers fecundity and ultimately the population of insect pest [233]. Fumigant toxicity of caryophyllene oxide may result from the inhibition of the mitochondrial electron transport system because changes in the concentration of oxygen or carbon dioxide may affect respiration rate of insect, thus, eliciting fumigant toxicity effects [234]. Thus, in conclusion plant derived essential oils and its constituents exert its toxicity in insects by interfering with the nervous co-ordination and respiratory system. 4. SYNERGISTIC ACTION OF ESSENTIAL OILS Chemical control of insect pest involving synthetic insecticides has induced resistance in several insects. Thus, the current aim of pests control stratigies is to produce plant based formulations which reduce the risk of developing resistance against insecticide. None of the plant products alone provide adequate crop protection, but attemps in this direction have been started. Applications of botanical preparations increase the farmer’s confidence in indigenous technology [235]. Although repellent activity of essential oils is generally attributed to some particular compounds, a synergistic phenomenon among these metabolites may result in a higher bioactivity compared to isolated components [236]. Omolo et al. have compared repellent activities between essential oil and synthetic oils formulated with its major constituents [152]. The activities of synthetic oils have been much smaller than those of corresponding natural essential oil. This indicates that minor constituents also contribute to repellent activity. This reflects the importance of compositional complexity in providing bioactivity to natural mixtures. It has been suggested that this is due to the fact that plant’s defense system exists as a suite of compounds not as individual ones. Accordingly, minor constituents although found in low percentages may act as synergists enhancing the effectiveness of major constituents through a variety of mechanisms [237]. The components of synergistic combinations have diverse modes of actions and thus, efficacy of combined product is greater than sum total of known and unknown chemical components. Both positive and negative synergism can occur between essential oil and/or components. Essential oils combinations such as thyme, anise and saffron have been demonstrated for synergistic activity [238]. Hummelbrunner and Isman have reported that mixtures of different monoterpenes produce synergistic effect on mortality [180]. Chaubey has reported that mixture of T. ammi, A. graveolens and N. sativa essential oils cause reduction in oviposition and developmental inhibitory activities against T. castaneum at lower concentration than alone [200]. Terpenes, α-pinene and β-caryophyllene have been evaluated for their repellent, acute toxicity and developmental inhibitory activities alone and in binary combination against T. castaneum. Fumigation of larvae and adults of T. castaneum with these two compounds caused lethality in them. Median lethal concentration of α-pinene and β-caryophyllene binary combination against adults and larvae has been found lower than when used alone. Fumigation with two sublethal concentrations of these two compounds in binary combination reduce oviposition potential of adults and inhibited pupation and adult emergence in larvae more potently than used alone. This study concludes that these two volatile compounds in binary combination shows synergism and thus, can used as efficient insecticidal tool against T. castaneum [132]. Since essential oils are mixture of 20-60 chemical compounds of diverse nature, it will be difficult for the insects to develop Chaubey Essential oils as green pesticides of stored grain insects 226 European Journal of Biological Research 2019; 9(4): 202-244 resistance against them. This also suggests that essential oil constituents alone can be a weaker candidate than crude essential oil in insect pest management programme. 5. STRUCTURE-ACTIVITY RELATIONSHIPS IN ESSENTIAL OIL COMPONENTS The relation between chemical structures of essential oil’s constituents and their biological activity has been well documented. It has been reported that any change in molecular structure can change their biological activities. Modifications of chemical structure of monoterpenoids enhance biological properties of essential oils as a whole as well as monoterpenoids that contain functional groups. The activities of essential oils and their constituents depend on functional group and chemical properties such as volatility and molecular weights [239]. Scientists have studied correlation between chemical structure of essential oils constituents and their insecticidal activity. Essential oil from M. arvensis has been reported to have insecticidal activity. The L-menthol isolated from this oil and seven of its acyl derivatives have been evaluated against stored grain insect pests. It has been reported that menthyl propionate and L-menthol have high insecticidal activity. High activity of menthyl propionate as compared to L-menthol can be due to increasing number of methyl groups in side chain [173]. Due to nucleophilic properties of methyl group, increase in number of methyl groups on side chain cause decrease in positive charge (increase negative charge) on carbon atom. Therefore, high activity of menthyl propionate may be due to increasing negative charge on carbon atom because of the presence of two methyl groups. However, increase of electrophilic groups such as methyl groups in chain leads to increase the activity of a function carbon atom. Depending on the number of methyl groups, acetate derivative have slight activity while menthyl propionate have high insecticidal activity. Low activity of menthyl benzoate has been observed because they do not have methyl group and the benzene ring is attached directly to menthyl carbon. Activity of menthyl cinnnamate has been found moderate as it has a double bond and benzene ring is not directly attached to carbon atom [173, 240]. Benzene derivatives (eugenol, isoeugenol, methyl eugenol, safrole and isosafrole) and terpenes (cineole, limonene, p-cymine and α-pinene) have been evaluated for insecticidal activity [101]. It has been observed that derivatives of benzene have higher insecticidal activity than that of terpenes. This toxicity may be due to the active groups in benzene derivatives. The presence of double bond in the side chain of aromatic ring and the substitution of methoxy group play an important role in the toxicity of these analogues. The knock down and contact activity has been found to increase in methyl eugenol due to further methoxy group. The order of contact toxicity of these compounds is methyl-eugenol > isosafrole = eugenol > safrole. In contrast, when double bond in side chain is nearer to aromatic ring, fumigant toxicity is decreased. Therefore, safrole shows more fumigant activity than isosafrole. However, benzene derivatives have more insecticidal activity than monoterpenes [101]. Insecticidal activity of thymol, pulegone, trans-anethole and eugenol has been evaluated against S. litura [180]. Thymol has higher toxicity than pulegone, trans-anethole and eugenol against S. litura. The order of toxicity of these compounds observed is thymol > pulegone > trans-anethole > eugenol. The high toxicity of thymol as compared to other compounds has been attributed to the presence of methyl groups in the side chain. This effect can be due to electron-donating property of methyl groups which decrease positive charge on carbon atom of side chain. Further researches involving strcture- activity are required to enhance insecticidal potency of essential oil. Further studies should be carried out to investigate whether the alteration in structure of essential oil constituents can modify mode of action. Chaubey Essential oils as green pesticides of stored grain insects 227 European Journal of Biological Research 2019; 9(4): 202-244 6. MAMMALIAN TOXICITY OF ESSENTIAL OILS Before using essential oils and/or their constituents as stored grain protectants, their probable toxicity in non-target animals including mammals must be acknowledged. The common use of plant essential oils in drugs and foods clearly indicate that essential oils show insignificant toxicity towards mammals. In general, most of the essential oils and their active constituents are nontoxic to mammals [241]. However, some essential oil/constituents are toxic to human and other mammals. The LD50 for toxic constituents against rats ranges from 800 to 3,000 mg/kg. Pulegone has been found toxic to rats with LD50 150 mg/kg intraperitoneally [242]. Also, thujone oil is very toxic to rats with LD50 45 mg/kg intraperitoneally [243]. Being a mixture of several constituents, essential oils seem to have no specific cellular targets [244]. Since essential oils are lipophilic in nature, they pass through cytoplasmic membrane and disrupt membrane structure leading to cytotoxicity. In eukaryotic cells, essential oils can induce depolarization of mitochondrial membranes by interfering with various ion channels [245, 246]. They change fluidity of membranes which become abnormally permeable resulting in leakage of radicals, cytochrome C, calcium ions and proteins similar to oxidative stress and bioenergetic failure. Permeability of outer and inner mitochondrial membranes leads to cell death by apoptosis and necrosis [247, 248]. This cytotoxic property is of great importance in the applications of essential oils in insect pest management. Essential oils induce cytotoxicity in mammalian cells by inducing apoptosis and necrosis. Since most essential oils have been found to be cytotoxic without being mutagenic, it is likely that most of them are also devoid of carcinogenicity. However, some essential oils and their constituents are considered as secondary carcinogens after metabolic activation [249]. Salvia sclarea and Melaleuca quinquenervia oils induce estrogen secretions which can cause estrogen-dependent cancers. Some others contain photosensitizing molecules like flavins, cyanin, porphyrins, hydrocarbures which can cause skin cancer. Estragole, a constituent of Ocimum basilicum and Artemisia dracunculus oils has shown carcinogenic properties in rat and mouse [250, 251]. Psoralen, a photosensitizing molecule found in some essential oils like Citrus aurantium can induce skin cancer after formation of covalent DNA adducts under ultraviolet A or solar light [252]. Pulegone, a component of essential oils of mint species can induce carcinogenesis [253]. Safrole, the major constituent of Sassafras albidum and Mespilodaphne pretiosa oils induces carcinogenic metabolites in rats [254]. Methyl eugenol has also been shown to be carcinogenic in rats [254]. The most necessary aspect of using essential oils and/or their constituents for pest control is assessment of their toxicity in mammals because many essential oils and their constituents are commonly used as culinary herbs and spices. Many of the commercial products based on essential oils are included in the GRAS (Generally Recognized as Safe) list by FDA (Food and Drug Administration) and EPA (Environmental Protection Agency) in USA for food and brevarage consumption [255]. Some of essential oil terpenoids are moderately toxic to mammals, but, with few exceptions, oils themselves or products based on oils are mostly nontoxic tomammals, birds and fish. Due to their volatility, oils and their constituents are environmentally nonpersistent with outdoor half lives of 24 hours on surfaces, in soil and in water [256]. Because many conventional pesticides are harmful for public, botanical-based pesticides especially essential oils become a popular choice for insect pest management in storage. 7. ESSENTIAL OIL-BASED INSECTICIDES FROM RESEARCH TO MARKET From time immemorial with the beginging of human civilization and storage of grain against poor agriculture production and famine, insect species have been damaging stored grain. To protect the grains in storage from insect infestation, aromatic plants have been used traditionally worldwide. Thus, scientific Chaubey Essential oils as green pesticides of stored grain insects 228 European Journal of Biological Research 2019; 9(4): 202-244 communities have started re-evaluating these plants and their volatile oils against insect pests of stored grains. Commonly used essential oils and active substances to be used as insecticide takes a long time as certain toxicological and ecotoxicological tests are required for registering commercial products. The EcoSMART technologies (USA) have introduced some pesticides based on essential oils [256]. These formulations are based on cinnamon oil with cinnamaldehyde. The EcoSMART technologies have introduced other plant volatile based insecticides EcoPCOR. They contain eugenol and 2-phenethyl propionate as active ingredients. They are used against crawling and flying insects. The EcoTrolTM formulation is based on rosemary oil and is used as an insecticide on horticultural crops. Garlic oil-based insecticides have also been produced in the US. These formulations contain mint oil as the active ingredient. They are used in home and garden for pest control [257]. However, essential oils must have following properties to be used in insect pest management programme [256]: • Essential oil must be produced in large scale throughout the world. • They must have broad activity against insects due to their multiple modes and sites of action. • They must have a variety of actions such as insecticidal, attractive, repellent, fumigant and antifeedant. • Essential oils and their active constituents must be nontoxic to mammals including human. • Oils and active compounds must be environmentally non-persistent. • They must be effective under low pest pressure. • They must have a short residual half-life on plants. Inspite of promising activities of essential oils against several insects, some problems have registered regarding its commercial application in the field. For example, essential oil’s volatility, water solubility and oxidation play important role in essential oils activity, application and persistent. Therefore, these problems must be resolved before using essential oils as alternative to synthetic pesticides for pest control [258]. New formulations with nanotechnology ‘Nanoformulation’ can resolve these problems. The new trend for using nanoformulation leads to protect essential oils from degradation and to increase their residue half-life by reducing evaporation. Nanoformulations have properties of controlled release of essential oils and ease of application and handling [259]. These nanoformulations can enhance essential oils activity due to small particle size. Yang et al. have shown that loaded nanoparticles with garlic essential oils are effective against T. castaneum [260]. Anjali et al. have reported that insecticidal activity of neem oil increases in nanoemulision formulation [261]. This effect can be due to the smallest droplet size of essential oil nanoemulsion. New nanotechnology methods have been planned to control H. armigera [262]. This new method stabilizes Artemisia arborescens oil with better insecticidal activity. This stability can be due to built- in of essential oil with solid lipid nanoparticles and developed an emulsion. Nanoencapsulation of essential oils have been shown high repellent activity than essential oils [115]. Some patents involving essential oils have shown that majority of the inventions focus on household insects. A cleaning solution including clove essential oil and pyrethroid destroy eggs and larvae, and leave a residue to prevent reinfestation by Blattaria [263]. Several essential oil based formulations have been proposed to control mosquitoes and flies [264]. Spearmint, bitter almond and birch, Betula lenta bark essential oils have been incorporated into a mixture showing insecticide and insect repellent properties [265]. A large number of patents have been assigned for preservation of clothes from moths and beetles including application of a solution containing clove essential oil on woollen cloth [266]. More recently, wash fast insect-resistant fabrics have been created with partially or wholly hollow porous fibres coated with encapsulated insecticidal agents such as Eucalyptus oil [267]. Beside these domestic uses, essential oils have got applications in agriculture and the food industry. Essential oils can also be incorporated with polymers Chaubey Essential oils as green pesticides of stored grain insects 229 European Journal of Biological Research 2019; 9(4): 202-244 into sheets. Attractant adhesive films with essential oils have been prepared to control insects in agriculture and horticulture. Coating materials, useful in agricultural structures, include pine essential oils to enhance their insecticidal properties and repel harmful insects [268]. Adhesives containing acrylic polymers and essential oils have been shown killing effect for Blatella germanica [269]. Essential oils have also been shown some usefulness for building materials. A wood preservative solution mixed with eucalyptus oils pyrethroids and borax have common applications [270]. 8. SUMMARY Essential oils are produced as secondary metabolite in aromatic plants. These are complex mixtures of volatile compounds in different concentartions. These oils and its constituents have repellent, antifeedant, ovicidal, oviposition inhibitory and developmental inhibitory activities in insects. These interfere with the respiratory and nervous system of the insect. Thus, essential oils can be used as alternatives in insect management. Most of these oils are selective in their role with little or no harmful effect on the environment and the non-target organisms including human. The main aim of this review is to provide basic informations regarding essential oils, chemistry and their role in stored grain insect pest management. Conflict of Interest: The author declares no conflict of interest. REFERENCES 1. Bakkali F, Averbeck S, Averbeck D, Idaomar M. Biological effects of essential oils. Food Chem Toxicol. 2008; 46: 446-475. 2. Chang ST, Cheng SS. Antitermite activity of leaf essential oils and their constituents from Cinnamomum osmophloeum. J Agric Food Chem. 2002; 50: 1389-1392. 3. Gottlieb OR, Salatino A. Função e evolução de óleos essenciais e de suas estruturas secretoras. Ciênc Cult. 1987; 39(8): 707-716. 4. Svoboda K, Svoboda T, Syred A. A closer look: Secretory structure of aromatic and medicinal plants. Herbal Gram. 2001; 53: 34-43. 5. Combrinck S, Du Plooy GW, McCrindle RI, Botha BM. Morphology and histochemistry of the glandular trichomes of Lippia scaberrima (Verbenaceae). Annals Bot. 2007; 99: 1111-1119. 6. Voo SS, Grimes HD, Lange BM. Assessing the biosynthetic capabilities of secretory glands in citrus peel. Plant Physiol. 2012; 159: 81-94. 7. Sangwan NS, Farooqi AHA, Shabih F, RS Sangwan RS. Regulation of essential oil production in plants. Plant Growth Regul. 2001; 34: 3-21. 8. Lima HRP, Kaplan MAC, Cruz AVM. Influência dos fatores abióticos na produção e variabilidade de terpenóides em plantas. Floresta Ambient. 2003; 10(2): 71-77. 9. Gobbo-Neto L, Lopes NP. Plantas medicinais: fatores de influência no conteúdo de metabólitos secundários. Quim Nova. 2007; 30(2): 374-381. 10. Bowles EJ. 2003. The Chemistry of Aromatherapeutic Oils. 3rd edn. Griffin Press. 11. Skold M, Karlberg AT, Matura M, Borje A. The fragrance chemical-caryophyllene-air oxidation and skin sensitization. Food Chem Toxicol. 2006; 44: 538-545. 12. Skold M, Hagvall L, Karlberg AT. Autoxidation of linalyl acetate, the main compound of lavender oil, creates potent contact allergens. Contact Dermatitis. 2008; 58: 9-14. Chaubey Essential oils as green pesticides of stored grain insects 230 European Journal of Biological Research 2019; 9(4): 202-244 13. Batish DR, Singh HP, Kohli RK, Kaur S. Eucalyptus essential oil as a natural pesticide. Forest Ecol Manag. 2008; 256: 2166-2174. 14. Vekiari SA, Protopapadakis EE, Papadopoulou P, Papanicolaou D, Panou C, Vamvakias M. Composition and seasonal variation of the essential oil from leaves and peel of a Cretan lemon variety. J Agri Food Chem. 2002; 50: 147-153. 15. Crescimanno F, De Pasquale F, Germana M, Bazan E, Palazzolo E. Annual variation of essential oils in the leaves of four lemon [Citrus limon (L.) Burm. f.] cultivars. In: Goren R, Mendel K, eds. Citriculture: proceedings of the Sixth International Citrus Congress: Middle East, Tel Aviv, Israel. International Citrus Congress Balaban Publishers, 1988: 583-588. 16. Brieskorn CH, Noble P. Two furanoeudesmanes from the essential oil of myrrh. Phytochem. 1983; 22: 187- 189. 17. Zygadlo JA. Antifungal properties of the leaf oils of Tagetes minuta L. and T. filifolia Lag. J Essent Oil Res. 1994; 6: 617-621. 18. Paranagama PA, Wimalasena S, Jayatilake GS, Jayawardhena AL, Senanayaka UM, Mubarak AM. A comparison of essential oil constituent of bark, leaf, root and fruit of cinnamon (Cinnamomum zeylanicum) grown in Sri Lanka. J Nat Sci Found Sri Lanka. 2001; 29: 147-153. 19. Başer KHC, Demirci B, Dekebo A, Dagne E. Essential oils of some Boswellia spp., Myrrh and Opopanax. Flavour Fragr J. 2003; 18: 153-156. 20. Cruz-Cañizares JDL, Doménech-Carbó MT, Gimeno-Adelantado JV, Mateo-Castro R, Bosch-Reig F. Study of Burseraceae resins used in binding media and varnishes from artworks by gas chromatography mass spectrometry and pyrolysis gas chromatography mass spectrometry. J Chromatography A. 2005; 1093: 177-194. 21. Ayédoun MA, Sohounhloué DK, Menut C, Lamaty G, Molangui T, Casanova J. Aromatic plants of tropical West Africa. VI. α-Oxobisabolene as main constituent of the leaf essential oil of Commiphora africana (A. Rich.) Engl, from Benin. J Essent Oil Res. 1998; 10: 105-107. 22. Avlessi F, Alitonou GA, Sohounhloue DK, Bessiere JM, Menut C. Aromatic Plants of Tropical West Africa. Part XV. Chemical and biological evaluation of leaf essential oil of Commiphora africana from Benin. J Essent Oil Res. 2005; 17: 569-571. 23. Zoghbi MDGB, Andrade EHA, Lima MDP, Silva TMD, Daly DC. The essential oils of five species of Protium growing in the North of Brazil. J Essent Oil Bearing Plants. 2005; 8: 312-317. 24. Maradufu A, Warthen JD. Furano sesquiterpenoids from Commiphora myrrh oil. Plant Sci. 1988; 57: 181- 184. 25. Marongiu B, Piras A, Porcedda S, Scorciapino A. Chemical composition of the essential oil and supercritical CO2 extract of Commiphora myrrha (Nees) Engl. and of Acorus calamus L. J Agric Food Chem. 2005; 53: 7939-7943. 26. Bandeira PN, Machado MIL, Cavalcanti FS, Lemos TLG. Essential oil composition of leaves, fruits and resin of Protium heptaphyllum (Aubl.) March. J Essent Oil Res. 2001; 13: 33-34. 27. Zoghbi MDGB, Maia JGS, Luz AIR. Volatile constituents from leaves and stems of Protium heptaphyllum (Aubl.). J Essent Oil Res. 1995; 7: 541-543. 28. Politeo O, Juki M, Milo M. Chemical composition and antioxidant activity of essential oils of twelve spice plants. Croatica Chemica Acta. 2006; 79(4): 545-552. 29. Giang PM, Konig WA, Son PT. Chemical composition of the resin essential oil of Canarium album from Vietnam. Chem Nat Comp. 2006; 42: 523-524. Chaubey Essential oils as green pesticides of stored grain insects 231 European Journal of Biological Research 2019; 9(4): 202-244 30. Viuda-Martos M, Ruíz-Navajas Y, Fernández-López J, Pérez-Álvarez JA. Chemical Composition of the essential oils obtained from some spices widely used in Mediterranean region. Acta Chim Slov. 2007; 54: 921-926. 31. Jilani G, Saxena RC, Rueda BP. Repellent and growth inhibiting effects of turmeric oil, sweetflag oil, neem oil and Margosan-O on red flour beetle (Coleoptera: Tenebrionidae). J Econ Entomol. 1988; 81: 1226- 1230. 32. Sangun MK, Aydin E, Timur M, Karadeniz H, Caliskan M, Ozkan A. Comparison of chemical composition of the essential oil of Laurus nobilis L. leaves and fruits from different regions of Hatay, Turkey. J Environ Biol. 2007; 28(4): 731-733. 33. Camarda L, Dayton T, Di Stefano V, Pitonzo R, Schillaci D. Chemical composition and antimicrobial activity of some oleogum resin essential oils from Boswellia spp. (Burseraceae). Ann Chim. 2007; 97: 837- 844. 34. Gary YD, Sue C, Herve C, Marie-Claude B, Danilo M. Essential oil of Bursera graveolens (Kunth) Triana et Planch from Ecuador. J Essent Oil Res. 2007; 19: 525-526. 35. Sylvestre M, Longtin APA, Legault J. Volatile leaf constituents and anticancer activity of Bursera simaruba (L.) Sarg. essential oil. Nat Prod Commun. 2007; 2: 1273-1276. 36. Verghese J, Joy MT, Retamar JA, Malinskas GG, Catalán CAN, Gros EG. A fresh look at the constituents of Indian olibanum oil. Flavour Fragr J. 1987; 2: 99-102. 37. Kasali AA, Adio AM, Oyedeji AO, Eshilokun AO, Adefenwa M. Volatile constituents of Boswellia serrata Roxb. (Burseraceae) bark. Flavour Fragr J. 2002; 17: 462-464. 38. Singh B, Kumar R, Bhandari S, Pathania S, Lal B. Volatile constituents of natural Boswellia serrata oleogum-resin and commercial samples. Flavour Fragr J. 2007; 22: 145-147. 39. Park IK, Kim J, Lee SG, Shin SC. Nematicidal activity of plant essential oils and components from Ajowan (Trachyspermum ammi), Allspice (Pimenta dioica) and Litsea (Litsea cubeba) essential oils against pine wood nematode (Bursaphelenchus xylophilus). J Nematol. 2007; 39: 275-279. 40. Onocha PA, Ekundayo O, Oyelola O, Laakso I. Essential oils of Dacryodes edulis (G. Don) H. J. Lam (African pear). Flavour Fragr J. 1999; 14: 135-139. 41. Obame LC, Edou P, Bassolé IHN, Koudou J, Agnaniet H, Eba F. Chemical composition, antioxidant and antimicrobial properties of the essential oil of Dacryodes edulis (G. Don) H. J. Lam from Gabon. Afr J Microbiol Res. 2008; 2: 148-152. 42. Koudou J, Edou P, Obame LC, Bassole IH, Figueredo G, Agnaniet H. Volatile components, antioxidant and antimicrobial properties of the essential oil of Dacryodesedulis G. Don from Gabon. J App Sci. 2008; 8: 3532-3535. 43. Harrasi AA, Saidi SA. Phytochemical analysis of the essential oil from botanically certified oleogum resin of Boswellia sacra (Omani Luban). Molecules. 2008; 13: 2181-2189. 44. Ali NAA, Wurster M, Arnold N, Teichert A, Schmidt J, Lindequist U. Chemical composition and biological activities of essential oils from the oleogum resins of three endemic soqotraen Boswellia species. Rec Nat Prod. 2008; 2: 6-12. 45. Knio KM, Usta J, Dagher S, Zournajian H, Kreydiyyeh S. Larvicidal activity of essential oils extracted from commonly used herbs in Lebanon against the seaside mosquito, Ochlerotatus caspius. Biores Tech. 2008; 99: 763-768. 46. Rezaeinodehl A, Khangholi S. Chemical composition of the essential oil of Artemisia absinthium growing wild in Iran. Pak J Biol Sci. 2008; 11: 946-949. Chaubey Essential oils as green pesticides of stored grain insects 232 European Journal of Biological Research 2019; 9(4): 202-244 47. Najda A, Dyduch M. Contents and chemical composition of essential oils from wild strawberry (Fragaria vesca L.). Herba Pol. 2009; 55: 153-162. 48. Arthur OT, Michael JM, Rebecca CB, Leslie RL, Dary L. Essential oils from the oleo-gum-resins of elephant tree or torote (Bursera microphylla A. Gray, Burseraceae) from Arizona. J Essent Oil Res. 2009; 21: 57. 49. Ali NAA, Wurster M, Lindequist U. Chemical composition of essential oil from the oleogum resin of Commiphora habessinica (Berg.) Engl. from Yemen. J Essent Oil Bearing Plant. 2009; 12: 244-249. 50. Azizi M, Davareenejad G, Bos R, Woerdenbag HJ, Kayser O. Essential oil content and constituents of black Zira (Bunium persicum [Boiss.] B. Fedtsch.) from Iran during field cultivation (Domestication). J Essent Oil Res. 2009; 21: 78-82. 51. Cheng SS, Chua MT, Chang ED, Huang CG, Chen WJ, Chang ST. Variations in insecticidal activity and chemical composition of leaf essential oils from Cryptomeria japonica at different ages. Biores Tech. 2009; 100: 465-470. 52. Islam R, Khan RI, Al-Reza SM, Jeong YT, Song CH, Khalequzzaman M. Chemical composition and insecticidal properties of Cinnamomum oil against the store product beetle Callosobruchus maculatus (F.). J Sci Food Agri. 2009; 89: 1241-1246. 53. Urzua A, Santander R, Echeverria J, Cabeza N, Palacios S, Rossi Y. Insecticidal properties of the essential oils from Haplopappus foliosus and Bahia ambrosoides against the house fly, Musca domestica L. J Chil Chem Soc. 2010; 55: 392-395. 54. Marzec MA, Polakowski C, Chilczuk R, Kołodziej B. Evaluation of essential oil content, its chemical composition and price of thyme (Thymus vulgaris L.) raw material available in Poland. Herba Pol. 2010; 56: 37-52. 55. Martins AP, Salgueiro LR, Gonçalves MJ, Cunha APD, Vila R, Cañigueral S. Essential oil composition and antimicrobial activity of Santiria trimera Bark. Planta Med. 2003; 69: 77-79. 56. Bikanga R, Makani T, Agnaniet H, Obame LC, Abdoul-Latif FM, Lebibi J. Chemical composition and biological activities of Santiria trimera (Burseraceae) essential oils from Gabon. Nat Prod Commun. 2010; 5: 961-964. 57. Michel JDP, François T, Bernadin N, Wilson A, Bertrand S, Amvam ZPH. Chemical characterization, antiradical, antioxidant and anti-inflammatory potential of the essential oils of Canarium schweinfurthii and Aucoumea klaineana (Burseraceae) growing in Cameroon. Agr Biol J N Am. 2010; 1: 606-611. 58. Ortet R, Thomas OP, Regalado EL, Pino JA, Filippi JJ, Fernández MD. Composition and biological properties of the volatile oil of Artemisia gorgonum Webb. Chem Biodivers. 2010; 7: 1325-1332. 59. Fang R, Jiang CH, Wang XY, Zhang HM, Liu ZL, Zhou L, Du SS, Deng ZW. Insecticidal activity of essential oil of Carum carvi fruits from China and its main components against two grain storage insects. Molecules. 2010; 15: 9391-9402. 60. Romeilah RM, Fayed SA, Mahmoud GI. Chemical compositions, antiviral and antioxidant activities of seven essential oils. J Appl Sci Res. 2010; 6(1): 50-62. 61. Meshkatalsadat MH, A Bamonori, H Batooli. The bioactive and volatile constituents of Prangos acaulis (DC) Bornm extracted using hydrodistilation and nano scale injection techniques. Digest J Nanomat Biostruc. 2010; 5(1): 263-266. 62. Conti B, Canale A, Bertoli A, Gozzini F, Pistelli L. Essential oil composition and larvicidal activity of six Midterranean Aromatic plants against mosquito Aedes albopictus (Diptera: Culicidae). Parasitol Res. 2010; 107: 1455-1461. Chaubey Essential oils as green pesticides of stored grain insects 233 European Journal of Biological Research 2019; 9(4): 202-244 63. Oskuee RK, Behravan J, Ramenzani M. Chemical composition, antimicrobial activity and antiviral activity activity of essential oil of Carum capticum from Iran. Avicenna J Phytomed. 2011; 1: 83-90. 64. Prieto JA, Patino OJ, Delgado WA, Moreno JP, Cuca LE. Chemical composition, insecticidal and antifungal activities of fruit essential oils of three Colombian Zanthoxyllum species. Chilean J Agri Res. 2011; 71: 73-82. 65. Barroso MST, Villanueva G, Lucas AM, Perez GP, Vargas RMF, Brun GW, Cassel E. Supercritical fluid extraction of volatile and non-volatile compounds from Schinus molle L. Brazilian J Chem Engin. 2011; 28: 305-312. 66. Pal M, Verma RK, Tewari SK. Anti-termite activity of essential oil and its components from Myristica fragrans against Microcerotermes beesoni. J Appl Sci Environ Manag. 2011; 15(4): 597-599. 67. Mothana RAA, Hasson SS, Schultze W, Mowitz A, Lindequist U. Phytochemical composition and in vitro antimicrobial and antioxidant activities of essential oils of three endemic soqotraen Boswellia species. Food Chem. 2011; 126: 1149-1154. 68. Khalfallah A, Labed A, Semra Z, AI-Kaki B, Kabouche A, Touzani R, Kabouche Z. 2011. Antibacterial activity and chemical composition of the essential oil of Ammi visnaga L. (Apiaceae) from Constantine, Algeria. Int J Med Aromatic Plant. 2011; 1(3): 302-305. 69. Zhao A, Yang X, Yang X, Wang W, Tao H. 2011. GC-MS analysis of essential oil from root of Angelica dahurica cv. Qibaizhi. Zhongguo Zhong Yao Za Zhi. 36(5): 603-607. 70. Elaissi A, Rouis Z, Abid N, Salem B, Mabrouk S, Ben Salem Y, Salah KBH, Aouni M, Farhat F, Chemli R, Harzallah-Skhiri F, Khouja ML. Chemical composition of 8 Eucalyptus species' essential oils and the evaluation of their antibacterial, antifungal and antiviral activities. BMC Complem Altern Med. 2012; DOI:10.1186/1472-6882-12-81. 71. Evergetis E, A Michaelakis, SA. Haroutounian. Essential oils of Umbelliferae (Apiaceae) family taxa as emerging potent agents for mosquito control. In: S. Soloneski (Ed.): Integrated Pest Management and Pest Control- Current and Future Tactices, In Tech. 2012: 613-638. 72. Abd-Elhady HK. Insecticidal activity and chemical composition of essential oil from Artemisia judaica L. against Callosobruchus maculatus (F.) (Coleoptera: Bruchidae). J Plant Protec. 2012; 52: 347-352. 73. Boukhris M, Regane G, Yangui T, Sayad S, Bouaziz M. Chemical composition and biological potential of essential oil from Tunisian Cupressus sempervirens L. J Arid Land Studies. 2012; 22: 329-332. 74. Sellamia IH, Bettaieba I, Bourgoua S, Dahmania R, Limama F, Marzouka B. Essential oil and aroma composition of leaves, stalks and roots of celery (Apium graveolens var. dulce) from Tunisia. J Essent Oil Res. 2012; 4(6): 513-521. 75. Lopez MD, Jordan MJ, Pascual-Villalobus MJ. Toxic compounds in essential oils of coriander, caraway and basil active against stored rice pests. J Stored Prod Res. 2008; 44: 273-278. 76. Carvalho LE, Magalhaes LAM, Lima MP, Marques MOM, Facanli R. Essential oils of Protium of Adolpho crassipetalum reserve: Protium crassipetalum, P. heptaphyllum subs. ulei, P. pilosissimum and P. polybotryum. J Essent Oil Bearing Plants. 2013; 4: 551-554. 77. Afoulous S, Ferhout H, Raoelison EG, Valentin A, Moukarzel B, Couderc F. Chemical composition and anticancer, antiinflammatory, antioxidant and antimalarial activities of leaves essential oil of Cedrelopsis grevei. Food Chem Toxicol. 2013; 56: 352-362. 78. Al Maofari A, El Hajjaji S, Debbab A, Zaydoun S, Ouaki B, Charof R, Mennane Z, Hakiki A, Mosaddak M. Chemical composition and antibacterial properties of essential oils of Pimpinella Anisum L. growing in Morocco and Yemen. Sci Study Res. 2013; 14(1): 11-16. Chaubey Essential oils as green pesticides of stored grain insects 234 European Journal of Biological Research 2019; 9(4): 202-244 79. El-Hawary SS, El-Tantawy ME, Rabeh MA, Badr WK. Chemical composition and biological activities of essential oils of Azadirachta indica A. Juss. Int J Appl Res Nat Prod. 2013; 6(4): 33-42. 80. Medzegue MJ, Stokes A, Gardrat C, Grelier S. Analysis of volatile compounds in Aucoumea klaineana oleoresin by static headspace/gas chromatography/mass spectrometry. J Nat Prod. 2013; 6: 81-89. 81. Cole ER, dos Santos RB, Júnior VL, Martins JDL, Greco SJ, Neto AC. Chemical composition of essential oil from ripe fruit of Schinus terebinthifolius Raddi and evaluation of its activity against wild strains of hospital origin. Braz J Microbiol. 2014; 45(3): 821-828. 82. de Miranda CASF, Cardoso MDG, de Carvalho MLM, Figueiredo ACS, Nelson DL, de Oliveira CM, Gomes MDS, de Andrade J, de Souza JA, de Albuquerque LRM. Chemical composition and allelopathic activity of Parthenium hysterophorus and Ambrosia polystachya weeds essential oils. Am J Plant Sci. 2014; 5: 1248-1257. 83. Nasser M, Housheh S, Kourini A, Maala N. Chemical composition of essential oil from leaves and flowers of Inula viscosa (L.) in Al-Qadmous region, Syria. Int J Pharm Sci Res. 2014; 5(12): 5177-5182. 84. Sharopov FS, Zhang H, Setzer WN. Composition of geranium (Pelargonium graveolens) essential oil from Tajikistan. Am J Essent Oils Nat Prod. 2014; 2(2): 13-16. 85. Abdellatif F, Hassani A. Chemical composition of the essential oils from leaves of Melissa officinalis extracted by hydrodistillation, steam distillation, organic solvent and microwave hydrodistillation. J Mater Environ Sci. 2015; 6(1): 207-213. 86. Vazirian M, Mohammadi M, Farzaei MH, Amin G, Amanzadeh Y. Chemical composition and antioxidant activity of Origanum vulgare subsp. vulgare essential oil from Iran. Res J Pharmacogn. 2015; 2(1): 41-46. 87. Al-Shuneigat JM, Al-Tarawneh IN, Al-Qudah MA, Al-Sarayreh SA, Al-Saraireh YM, Alsharafa KY. The chemical composition and the antibacterial properties of Ruta graveolens L. essential oil grown in Northern Jordan. Jordan J Biol Sci. 2015; 8(2): 139-143. 88. Dai DN, Thang TN, Ogunmoye AR, Eresanya OI, Ogunwande IA. Chemical constituents of essential oils from the leaves of Tithonia diversifolia, Houttuynia cordata and Asarumglabrum grown in Vietnam. Am J Essent Oils Nat Prod. 2015; 2(4): 17-21. 89. Thomas S, Mani B. Chemical composition, antibacterial and antioxidant properties of essential oil from the rhizomes of Hedychium forrestii var. palaniense Sanoj and M. Sabu. Indian J Pharm Sci. 2016; 78(4): 452- 457. 90. Koul O, Walia S, Dhaliwal GS. Essential oils as green pesticides: Potential and constraints. Biopestic Int. 2008; 4: 63-84. 91. Van Zyl RL, Seatlholo ST, van Vuuren SF. The biological activities of 20 nature identical essential oil constituents. J Essent Oil Res. 2006; 18: 129-133. 92. Yang P, Ma Y, Zheng S. Adulticidal activity of five essential oils against Culex pipiens quinquefasciatus. J Pesticide Sci. 2005; 30: 84-89. 93. Kostyukovsky M, Rafaeli A, Gileadi C, Demchenko N, Shaaya E. Activation of octopaminergic receptors by essential oil constituents isolated from aromatic plants: possible mode of action against insect pests. Pest Manag Sci. 2002; 58: 1101-1106. 94. Petroski RJ, Hammack L. Structure activity relationships of phenyl alkyl alcohols, phenyl alkyl amines and cinnamyl alcohol derivatives as attractants for adult corn root worm (Coleopteran: Chrysomelidae: Diabrotica sp.). Environ Entomol. 1998; 27: 688-694. 95. Pair SD, Horvat RJ. Volatiles of Japanese honeysuckle flowers as attractants for adult Lepidopteran insects. 1997; US Patent, 5665344. Chaubey Essential oils as green pesticides of stored grain insects 235 European Journal of Biological Research 2019; 9(4): 202-244 96. Vargas RI, Stark JD, Kido MH, Ketter HM, Whitehand LC. Methyl-eugenol and cuelure traps for suppression of male oriental fruit flies and melon flies (Diptera: Tephritidae) in Hawaii: Effects of lure mixtures and weathering. J Econ Entomol. 2000; 93: 81-87. 97. Katerinopoulos H, Pagona G, Afratis A, Stratigaki N, Roditakis N. Composition and insect attracting activity of the essential oil of Rosmarinus officinalis. J Chem Ecol. 2005; 31: 111-122. 98. Copping LG, Duke SO. Natural products that have been used commercially as crop protection agents. Pest Manag Sci. 2007; 63: 524-554. 99. Harrewijn P, Oosten AM, Piron PGM. 2001. Natural terpenoids as messengers. Dordrecht: Kluwer Academic Publishers. 100. Kokate CK, D’Cruz JL, Kumar RA, Apte SS. Antiinsect and juvenoidal activity of phytochemicals derived from Adhatoda vasica Nees. Indian J Nat Prod. 1985; 1: 7-9. 101. Ngoh SP, Choo LEW, Pang FY, Huang Y, Kini MR, Ho SH. Insecticidal and repellent properties of nine volatile constituents of essential oils against the American cockroach, Periplaneta americana (L.). Pest Sci. 1998; 54: 261-268. 102. Hassalani A, Lwande W. Anti pest secondary metabolites from African plants. In JT Arnason, BJR Philogene, P Morand, eds. Insecticides of plant origin. American Chemical Society Symposium series. 1989; 387: 78-94. 103. Mwangi JW, Addae-Mensah I, Muriuki G, Munavu R, Lwande W, Hassanali A. Essential oils of Lippia species in Kenya IV: Maize weevil (Sitophilus zeamais) repellency and larvicidal activity. Int J Pharm. 1992; 30: 9-16. 104. Kalemba D, Kurowska A, Gora J, Lis A. Analysis of essential oils: influence of insects. Part V. Essential oil of the berries of Juniper (Juniperus communis L.). Pestycydy. 1991; 2: 31-34. 105. Nawrot J. Principles for grain weevil (Sitophilus granaries L.) (Coleoptera: Cuculionidae) control with use of natural chemical compounds affecting the behavior of beetles. Prace Naukowe Instytutu Ochrony Roślin. 1983; 24: 173-197. 106. Kalemba D, Gora J, Kurowska A, Majda T, Mielniczuk Z. Analysis of essential oils in aspect of their influence on insects. Part I. Essential oils of Absinthium. Zeszyty Naukowe Politechniki Łódzkiej, Technologia Chemia Spożywcza. 1993; 589: 5-14. 107. Chahal KK, Arora M, Joia BS, Chhabra BR. Bioefficacy of turmeric oil against Tribolium castaneum (Herbst) under laboratory conditions. In: Dilawari VK, Deol GS, Joia BS, Chuneja PK. (eds.), Proc. 1st Congress on Insect Science: Contributed Papers, PAU Ludhiana. 2005: 147-148. 108. Garcia M, Donadel OJ, Ardanaz CE, Tonn CE, Sosa ME. Toxic and repellent effects of Baccharis salicifolia essential oil on Tribolium castaneum. Pest Manag Sci. 2005; 61: 612-618. 109. Stefanazzi N, Gutierrez MM, Stadler T, Bonini NA, Ferrero AA. Biological activity of essential oil of Tagetes terniflora Kunth (Astereaceae) against Tribolium castaneum Herbst (Insecta, Coleoptera, Tenebrionidae). Bol Sanidad Veg Plagas. 2006; 32(3): 439-447. 110. Wang D, Collins PJ, Gao X. Optimising indoor phosphine fumigation of paddy rice bag-stacks under sheeting for control of resistant insects. J Stored Prod Res. 2006; 42: 207-217. 111. Jaenson TG, Palsson K, Borg-Karlson AK. Evaluation of extracts and oils of mosquito (Diptera: Culicidae) repellent plants from Sweden and Guinea-Bissau. J Med Entomol. 2006; 43: 113-119. 112. Toloza AC, Lucia A, Zerba E, Masuh H, Picollo MI. Interspecific hybridization of eucalyptus as a potential tool to improve the bioactivity of essential oils against permethrin-resistant head lice from Argentina. Biores Technol. 2008; 99: 7341-7347. Chaubey Essential oils as green pesticides of stored grain insects 236 European Journal of Biological Research 2019; 9(4): 202-244 113. Ahmed R, Mahmood A, Rashid F, Ahmad Z, Nadir M, Naseer Z, Kosar S. Chemical constituents of seed (kernel) of Prunus domestica and their insecticidal and antifungal activities. J Saudi Chem Soc. 2007; 11(1): 121-130. 114. Shakarami J, Kamali K, Moharamipour S. Fumigant toxicity and repellency effect of essential oil of Salvia bracteata on four species of warehouse pests. J Entomol Soc Iran. 2005; 24: 35-50. 115. Negahban M, Moharramipour S, Zand M, Hashemi SA. Repellent activity of nanoencapsulated essential oil of Artemisia sieberi Besser on Plutella xylostella L. larvae. Iran J Med Aromatic Plants. 2014; 29: 909- 924. 116. Ahmed ME, El-Salam A. Fumigant toxicity of seven essential oils against the cowpea weevil, Callosobruchus maculatus (F.) and the rice weevil, Sitophilus oryzae (L.). Egypt Acad J Biolog Sci. 2010; 2(1): 1-6. 117. Chaubey MK. Insecticidal activity of Trachyspermum ammi (Umbelliferae), Anethum graveolens (Umbelliferae) and Nigella sativa (Ranunculaceae) essential oils against stored-product beetle Tribolium castaneum herbst (Coleoptera: Tenebrionidae). Afri J Agric Res. 2007; 2(11): 596-600. 118. Chaubey MK. Toxicity of essential oils from Cuminum cyminum (Umbelliferae), Piper nigrum (Piperaceae) and Foeniculum vulgare (Umbelliferae) against stored product beetle Tribolium castaneum Herbst (Coleoptera: Tenebrionidae). Elect J Envir Agri Food Chem. 2007; 6(1): 1719-1727. 119. Sahaf BZ, Moharramipour S, Meshkatalsadat MH, Filekesh E. Repellent activity and persistence of the essential oils from Carum copticum and Vitex pseudonegundo on Tribolium castaneum. Integr Prot Stored Prod IOBC Bull. 2008; 40: 205-210. 120. Arabi F, Moharramipour S, Sefidkon F. Chemical composition and insecticidal activity of essential oil from Perovskia abrotanoides (Lamiaceae) against Sitophilus oryzae (Coleoptera: Curculionidae) and Tribolium castaneum (Coleoptera: Tenebrionidae). Int J Trop Insect Sci. 2008: 144-150. 121. Shukla J, Tripathi SP, Chaubey MK. Toxicity of Myristica fragrance and Illicium verum essential oils against flour beetle Tribolium castaneum Herbst (Coleoptera: Tenebrionidae). Elect J Envir Agri Food Chem. 2008; 7(7): 3059-3064. 122. Karahroodi ZR, Moharramipour S, Rahbarpour A. Investigated repellency effect of some essential oils of 17 native medicinal plants on adults Plodia interpunctella. Am Eurasian J Sustainable Agric. 2009; 3: 181- 184. 123. Zapata N, Smagghe G. Repellency and toxicity of essential oils from the leaves and bark of Laurelia sempervirens and Drimys winteri against Tribolium castaneum. Ind Crops Prod. 2010; 32: 405-410. 124. Abdel-Sattar E, Zaitoun AA, Farag MA, El Gayed SH, Harraz FMH. Chemical composition, insecticidal and insect repellent activity of Schinus molle L. leaf and fruit essential oils against Trogoderma granarium and Tribolium castaneum. Nat Prod Res. 2010; 24: 226-235. 125. Pavela R. Insecticidal and repellent activity of selected essential oils against of the pollen beetle, Meligethes aeneus (Fabricius) adults. Ind Crops Prod. 2011; 34: 888-892. 126. Chaubey MK. Insecticidal properties of Zingiber officinale and Piper cubeba essential oils against Tribolium castaneum Herbst (Coleoptera: Tenebrionidae). J Biol Active Prod Nat. 2011; 1(5&6): 306-313. 127. Akarami H, Moharramipour S, Imani S. Comparative effect of Thymus kotschyanus and Mentha longifolia essential oils on oviposition deterrence and repellency of Callosobruchus maculatus F. Iran J Med Aromat Plants. 2011; 27: 1-10. Chaubey Essential oils as green pesticides of stored grain insects 237 European Journal of Biological Research 2019; 9(4): 202-244 128. Saeidi M, Moharramipour S, Sefidkon F, Aghajanzadeh S. Insecticidal and repellent activities of Citrus reticulate, Citrus limon and Citrus aurantium essential oils on Callosobruchus maculatus. Integr Prot Stored Prod IOBC/WPRS Bull. 2011; 69: 289-293. 129. Jamal M, Moharramipour S, Zandi M, Negahban M. Ovicidal activity of nano-encapsulated essential oil of Carum copticum on diamondback moth Plutella xylostella. Proceedings of the 1st National Congress of Monitoring and Forecasting in Plant Protection. 2012; February 14-15, Borujerd, Iran, 128-129. 130. Chaubey MK. Responses of Tribolium castaneum (Coleoptera: Tenebrionidae) and Sitophilus oryzae (Coleoptera: Curculionidae) against essential oils and pure compounds. Herba Pol. 2012; 58(3): 33-35. 131. Pugazhvendan SR, Ross PR, Elumalai K. Insecticidal and repellant activities of plants oil against stored grain pest, Tribolium castaneum (Herbst) (Coleoptera:Tenebrionidae). Asian Pacific J Trop Dis. 2012: S412-S415. 132. Chaubey MK. Biological effects of essential oils against Rice weevil Sitophilus oryzae L. (Coleoptera: Curculionidae). J Essent Oil Bearing Plants. 2012; 15(5): 809-815. 133. Wang X, Hao Q, Chen Y, Jiang S, Yang Q, Li Q. The effect of chemical composition and bioactivity of several essential oils on Tenebrio molitor (Coleoptera: Tenebrionidae). J Insect Sci. 2015; 15: 116-122. 134. Chaubey MK. Fumigant and contact toxicity of Allium sativum (Alliaceae) essential oil against Sitophilus oryzae L. (Coleoptera: Dryophthoridae). (2016). Entomol Appl Sci Let. 2016; 3(2): 43-48. 135. Ukeh DA. Bioactivities of essential oil of Afromomum melegueta and Zingiber officinale both (Zingiberaceae) against Rhyzopertha dominica (Fabricius). J Entomol. 2008; 5(3): 193-199. 136. Cosimi S, Rossi E, Cioni PL, Canale A. Bioactivity and qualitative analysis of some essential oils from Mediterranean plants against stored-product pests: Evaluation of repellency against Sitophilus zeamais Motschulsky, Cryptolestes ferrugineus (Stephens) and Tenebrio molitor (L.). J Stored Prod Res. 2009; 45: 125-132. 137. Park IK, Choi KS, Kim DH, Choi IH, Kim LS, Bak WC, Choi JW, Shin SC. Fumigant activity of plant essential oils and components from horseradish (Armorcia rusticana), anise (Pimpinella anisum) and garlic (Allium sativum) oils against Lycoriella ingénue (Diptera: Sciaridae). Pest Manag Sci. 2006; 62: 723-728. 138. Park IK, Kim LS, Choi IH, Lee YS, Shin SC. Fumigant activity of plant essential oils and components from Schizonepeta tenuifolia against Lycoriella ingénue (Diptera: Sciaridae). J Ecol Entomol. 2006; 99: 1717-1721. 139. Kheradmand K, Sadat NSA, Sabahi G. Repellent effects of essential oil from Simmondasia chinensis (Link) against Oryzaephilus surinamensis Linnaeus and Callosobruchus maculatus Fabricius. Res J Agri Sci. 2010; 1(2): 66-68. 140. Kim SI, Yoon JS, Jung JW, Hong KB, Ahn YJ, Kwon HW. Toxicity and repellency of origanum essential oil and its components against Tribolium castaneum (Coleoptera: Tenebrionidae) adults. J Asia Pacific Entomol. 2010; 13: 369-373. 141. Liu ZL, Liu QR, Chu SS. Chemical composition and insecticidal activity against Sitophilus zeamais of the essential oil of Artemisia capillaries and Artemisia mongolica. Molecules. 2010; 15(4): 2600-2608. 142. Ajayi FA, Olonisakin A. Bioactivity of three essential oils extracted from edible seeds on the rust-red flour beetle, Tribolium castaneum (Herbst) infesting stored pearl millet. Trakia J Sci. 2011; 9(1): 28-36. 143. Gonzalez-Colomo A, Lopez-Balboa, Santana O, Reina M, Fraga BM. Terpene-based plant defenses. Phytochem Rev. 2011; 10: 245-260. Chaubey Essential oils as green pesticides of stored grain insects 238 European Journal of Biological Research 2019; 9(4): 202-244 144. Khani A, Asghari J. Insecticidal activities of Mentha longifolia, Pulicaria gnaphalodes and Achillea wilhelmsii against two stored product pests, the flour beetle, Tribolium castaneum, and the cowpea weevil, Callosobruchus maculatus. J Insect Sci. 2012; 12:73. 145. JM Ben Jemba, Tersim N, Toudert KT, Khouja ML. Insecticidal activities of essential oils from leaves of Laurus nobilis L. from Tunisia, Algeria and Morocco, and comparative chemical composition. J Stored Prod Res. 2012; 48: 97-104. 146. Ahn YJ, Lee SB, Lee HS, Kim GH. Insecticidal and acaricidal activity of carvacrol and $-thujaplicine derived from Thujopsis dolabrata var. hondai sawdust. J Chem Ecol. 1998; 24: 81-90. 147. Chaubey MK. Insecticidal effect of Allium sativum (Alliaceae) essential oil against Tribolium castaneum (Coleoptera: Tenebrionidae). TBAP. 2013; 3(4): 248-258. 148. Paruch E, Ciunik Z, Nawrot J, Wawrzenczyk C. Lactones: Synthesis of terpenoids lactones active insect antifeedants. J Agric Food Chem. 2000; 48: 4973-4977. 149. Agrawal M, Walia S, Dhingra S. Insect growth inhibition, antifeedant and antifungal activity of compounds isolated/derived frim Zingiber officinale rhizomes. Pest Manag Sci. 2000; 37: 289-300. 150. Tripathi A, Prajapati V, Aggarwal K, Kumar S. Toxicity, feeding deterrence, and effect of activity of 1,8- cineole from Artemisia annua on progeny production of Tribolium castanaeum (Coleoptera: Tenebrionidae). J Econ Entomol. 2001; 94: 979-983. 151. Tripathi AK, Prajapati V, Verma N, Bahl JR, Bansal RP, Khanuja SP, Kumar S. Bioactivities of the leaf essential oil of Curcuma longa (var. ch-66) on three species of stored-product beetles (Coleoptera). J Econ Entomol. 2002; 95(1): 183-189. 152. Tripathi AK, Prajapati V, Khanuja SP, Kumar S. Effect of d-limonene on three stored-product beetles. J Econ Entomol. 2003; 96(3): 990-995. 153. Huang Y, Ho SH. Toxicity and antifeedant activities of cinnamaldehyde against the grain storage insects, Tribolium castaneum (Herbst) and Sitophilus zeamais Motsch. J Stored Prod Res. 1998; 34(1): 11-17. 154. Fazolin M, Estrela JLV, Catani V, Lima MS, Alécio MR. Toxicity of Piper aduncum oil to adults of Cerotoma tingomarianus Bechyné (Coleoptera: Chrysomelidae). Neotrop Entomol. 2005; 34(3): 485-489. 155. Rana VS, Rashmi RD. Antifeedant and ovipositional activities of Vitex negundo leaves against Sitophilus oryzae and Callosobruchus chinensis. Shashpa. 2005; 12: 117-121. 156. Benzi V, Stefanazzi N, Ferrero AA. Biological activity of essential oils from leaves and fruits of pepper tree (Schinus molle L.) to control rice weevil (Sitophilus oryzae L.). Chilean J Agri Res. 2009; 69: 154- 159. 157. Ebadollahi A. Antifeedant activity of essential oils from Eucalyptus globules Labill and Lavandula stoechas L. on Tribolium castaneum Herbst (Coleoptera: Tenebrionidae). Biharean Biologist. 2011; 5(1): 8-10. 158. Don-Pedro KM. Investigation of single and joint fumigant insecticidal action of citrus peel oil components. Pestic Sci. 1996; 46: 79-84. 159. Regnault-Roger C, Hamraoui A. Inhibition of the reproduction of Acanthoscelides obtectus Say (Coleoptera), a kidney bean (Phaseolus vulgaris) bruchid, by aromatic essential oils. Crop Prot. 1994; 13: 624-628. 160. Elhag EA. Deterrent effects of some botanical products on oviposition of the cowpea bruchid Callosobruchus maculatus (F.) (Coleoptera: Bruchidae). Int J Pest Manag. 2000; 46: 109-113. 161. Dimetry NZ, Hafez M, Abbass MH. Efficiency of some oils and neem formulations against the cow pea beetle, Callosobruchus maculatus (Fabricius) Coleoptera: Bruchidae). In Koul O, Dhaliwal GS, Marwaha Chaubey Essential oils as green pesticides of stored grain insects 239 European Journal of Biological Research 2019; 9(4): 202-244 SS, Arora JK (eds.), Biopesticides and Pest Management, Vol. 2, Campus Books International, New Delhi, 2003: 1-10. 162. Brito JP, Baptistussi RC, Funichelo M, Oliveira JEM, Bortoli SA. Effect of essential oils of Eucalyptus spp. under Zabrotes subfasciatus (Both. 1833) (Coleoptera: Bruchidae) and Callosobruchus maculatus (Fabr. 1775) (Coleoptera: Bruchidae) in two beans species. Bol Sanidad Veg Plagas. 2006; 32(4): 573-580. 163. Chaubey MK. Fumigant Toxicity of essential oils from some common spices against pulse beetle Callosobruchus chinensis (Coleoptera: Bruchidae). J Oleo Sci. 2008; 57(3): 171-179. 164. Waliwitiya R, Kennedy CJ, Lowenberger CA. Larvicidal and oviposition-altering activity of monoterpenoids, trans-anethole and rosemary oil to the yellow fever mosquito Aedes aegypti (Diptera: Culicidae). Pest Manag Sci. 2009; 65: 241-248. 165. Nondenot ALR, Seri-Kouassi BP, Kouakou KH. Insecticidal activity of essential oils from three Aromatic Plants on Callosobruchus Maculatus F. in Côte D’ivoire. Eur J Sci Res. 2010; 39(2): 243-250. 166. Ho SH, Koh L, Ma Y, Huang Y, Sim KY. The oil of garlic, Allium sativum L. (Amaryllidaceae), as a potential grain protectant against Tribolium castaneum (Herbst) and Sitophilus zeamais Motsch. J Stored Prod Res. 1996; 34: 11-17. 167. Ho SH, Ma Y, Huang Y. Anethol, a potential insecticide for Illicium verum Hook F. against two stored product insects. Int Pest Control. 1997; 39: 50-51. 168. Tunc I, Berger BM, Erler F, Dagli F. Ovicidal activity of essential oils from five plants against two stored- product insects. J Stored Prod Res. 2000; 36: 161-168. 169. Lamiri A, Lhaloui S, Benjilali B, Berrada M. Insecticidal effects of essential oils against Hessian fly, Mayetiola desstructor (Say). Field Crops Res. 2001; 71: 9-15. 170. Choi WI, Lee EH, Choi BR, Park HM, Ahn YJ. Toxicity of plant essential oils to Trialeurodes vaporariorum (Homoptera: Aleyrodidae). J Ecol Entomol. 2003; 96(5): 1479-1484. 171. Mondal M, Khalequzzaman M. Toxicity of naturally occurring compounds of plant essential oil against Tribolium castaneum (Herbst). J Biol Sci. 2010; 10(1): 10-17. 172. Chaubey MK. Biological activities of Allium sativum essential oil against pulse beetle, Callosobruchus chinensis (Coleoptera: Bruchidae). Herba Pol. 2014; 60(2): 41-55. 173. Aggarwal KK, Tripathi AK, Ahmad A, Prajapati V, Verma N, Kumar S. Toxicity of L-menthol and its derivatives against four storage insects. Insect Sci Appl. 2001; 21: 229-235. 174. Ayvaz A, Sagdic O, Karaborklu S, Ozturk I. Insecticidal activity of the essential oils from different plants against three stored-product insects. J Insect Sci. 2010; DOI: 10.10.1673/031.010.2101. 175. Stefanazzi N, Stadler TA, Ferrero A. Composition and toxic, repellent and feeding deterrent activity of essential oils against the stored-grain pests Tribolium castaneum (Coleoptera: Tenebrionidae) and Sitophilus oryzae (Coleoptera: Curculionidae). Pest Mang Sci. 2011; 67: 639-646. 176. Ahmed SM, Eapen M. Vapour toxicity and repellency of some essential oils to insect pests. Indian Perf. 1986; 30: 273-278. 177. Singh D, Siddiqui MS, Sharma S. Reproductive retardant and fumigant properties in essential oils against rice weevil in stored wheat. J Econ Entomol. 1989; 82: 727-733. 178. Haubruge E, Lognay G, Marlier M, Danhier P, Gilson JC, Gaspar C. The toxicity of five essential oils extracted from Citrus species with regards to Sitophilus zeamais Motsch (Col., Curculionidae), Prostephanus truncatus (Horn) (Col., Bostrychidae) and Tribolium castaneum Herbst (Col., Tenebrionidae). Medelingen van de Faculteit Landbouwwetenschappen Rijksuniversiteit Gent. 1989; 54: 1083-1093. Chaubey Essential oils as green pesticides of stored grain insects 240 European Journal of Biological Research 2019; 9(4): 202-244 179. Kalemba D, Gora J, Kurowski A. Analysis of the essential oil of Solidago canadensis. Planta Med. 1990; 56: 222-223. 180. Hummelbrunner LA, Isman MB. Acute sublethal, antifeedant and synergistic effects of monoterpenoid essential oil compounds on the tobacco cutworm, Spodoptera litura (Lep. Noctuidae). J Agric Food Chem. 2001; 49: 715-720. 181. Tripathi AK, Prajapati V, Aggrawal KK, Khanuja SPS, Kumar S. Toxicity towards Tribolium castaneum in the fraction of essential oil of Anethum sowa seeds. J Med Arom Plant Sci. 2000; 22: 40. 182. Tripathi AK, Prajapati V, Aggrawal KK, Khanuja SPS, Kumar S. Repellency and toxicity of oil from Artemisia annua to certain stored product beetles. J Econ Entomol. 2000; 93: 43-47. 183. Verma N, Tripathi AK, Prajapati V, Bahl JR, Khanuja SPS, Kumar S. Toxicity of essential oil from Lippia alba towards stored grain insects. J Med Arom Plant Sci. 2000; 22: 50. 184. Huang Y, Lam SL, Ho SH. Bioactivities of essential oil from Elletaria cardamomum (L.) Maton. to Sitophilus zeamais Motschulsky and Tribolium castaneum Herbst. J Stored Prod Res. 2000; 36: 107-117. 185. Lee BH, Choi WS, Lee SE, Park BS. Fumigant toxicity of essential oils and their constituent compounds towards the rice weevil, Sitophilus oryzae (L.). Crop Prot. 2001; 20: 317-320. 186. Koul O, Singh G, Singh R, Singh J. Mortality and reproductive performance of Tribolium castaneum exposed to Anethol vapours at high temperature. Biopest Int. 2007; 3: 126-137. 187. Abdelgaleil SA, Mohamed MI, Badawy ME, El-Armani SA. Fumigant and contact toxicities of monoterpenes to Sitophilus oryzae (L.) and Tribolium castaneum (Herbst) and their inhibitory effects on acetylcholinesterase activity. J Chem Ecol. 2009; 35: 518-525. 188. Saleem M, Hussain D, Rashid RH, Saleem HM, Ghouse G, Abbas M. Insecticidal activities of two citrus oils against Tribolium castaneum (Herbst). Am J Res Comm. 2013; 1(6): 67-74. 189. Nowrouziasl F, Shakarami J, Shahryar J. Fumigation toxicity of essential oils from five species of Eucalyptus against adult of Sitophilus oryzae L. (Coleoptera: Curculionidae). Int J Agri Inn Res. 2014; 2(4): 2319-1473. 190. Saleem S, ul Hasan M, Sagheer M, Sahi ST. Insecticidal activity of essential oils of four medicinal plants against different stored grain insect pests. Pakistan J Zool. 2014; 46(5): 1407-1414. 191. Rozman V, Kalinovic I, Korunic Z. Toxicity of naturally occurring compounds of Lamiaceae and Lauraceae to three stored-product insects. J Stored Prod Res. 2007; 43: 349-355. 192. Papachristos DP, Stamopoulos DC. Repellent, toxic and reproduction inhibitory effects of essential oil vapours on Acanthoscelides obtectus (Say) (Coleoptera: Bruchidae). J Stored Prod Res. 2002; 38: 117-128. 193. Lee BH, Lee SE, Annis PC, Pratt SC, Park SB, Tumaalii F. Fumigant toxicity of essential oils and monoterpenes against the red flour beetle, Tribolium castaneum Herbst. J Asia-Pacific Entomol. 2002; 5: 237-240. 194. Kim SI, Park C, Ohh MH, Cho HC, Ahn YJ. Contact and fumigant activities of aromatic plant extracts and essential oils against Lasioderma serricorne (Coleoptera: Anobiidae). J Stored Prod Res. 2003; 39:1-19. 195. Kim SI, Roh JY, Kim DH, Lee HS, Ahn YJ. Insecticidal activities of aromatic plant extracts and essential oils against Sitophilus oryzae and Callosobruchus chinensis. J Stored Prod Res. 2003; 39: 293-303. 196. Sahaf BZ, Moharamipour S, Meshkatassadat MH. Chemical constituents and fumigant toxicity of essential oil from Carum copticum against two stored product beetles. Insect Sci. 2007; 14: 213-218. 197. Zoubiri S, Baaliouamer A. Essential oil composition of Coriandrum sativum seed cultivated in Algeria as food grains protectant. Food Chem. 2010; 122: 1226-1228. Chaubey Essential oils as green pesticides of stored grain insects 241 European Journal of Biological Research 2019; 9(4): 202-244 198. Manzoomi N, Ganbalani GN, Dastjerdi HR, Fathi SAA. Fumigant toxicity of essential oils of Lavandula officinalis, Artemisia dracunculus and Heracleum persicum on the adults of Callosobruchus maculatus (Coleoptera: Bruchidae). Munis Entomol Zool. 2010; 5(1): 118-122. 199. Taghizadeh-Sarikolaei A, Moharamipour S. Fumigant toxicity of essential oil from Thymus persicus (Lamiaceae) and Prangos acaulis (Apiaceae) against Callosobruchus maculatus (Coleoptera: Bruchidae). Plant Prot. 2010; 33(1): 55-68. 200. Chaubey MK. Fumigant toxicity of essential oils against rice weevil Sitophilus oryzae L. (Coleoptera: Curculionidae). J Biol Sci. 2011; 11: 411-416. 201. Ebadollahi A, Mahboubi. Insecticidal activity of essential oil isolated from Azilia eryngioides (Pau) Hedge Et Lamond against two beetle pests. Chilean J Agri Res. 2011; 71(3): 406-411. 202. Ebadollahi A. Susceptibility of two Sitophilus species (Coleoptera: Curculionidae) to essential oils from Foeniculum vulgare and Satureja hortensis. Ecol Balkanica. 2011; 3(2): 1-8. 203. Liu ZL, Chu SS, Jiang GH. Insecticidal activity and composition of essential oil of Ostericum sieboldii (Apiaceae) against Sitophilus zeamais and Tribolium castaneum. Rec Nat Prod. 2011; 5: 74-81. 204. Yeom HJ, Kang JS, Kim GH, Park IK. Insecticidal and acetylcholine esterase inhibition activity of Apiaceae plant essential oils and their constituents against adults of german cockroach (Blattella germanica). J Agr Food Chem. 2012; 60(29): 7194-7203. 205. Khani A, Rahdari T. Chemical composition and insecticidal activity of essential oil from Coriandrum sativum seeds against Tribolium confusum and Callosobruchus maculatus. Int Scholar Res Net. 2012; doi: 10.5402/2012/263517. 206. Izakmehri K, Saber M, Hassanpouraghdam MB. Lethal and sublethal effects of essential oils from Heracleum persicum Desf and Eucalyptus sp. as biopesticide against the adults of Callosobruchus maculatus F. (Coleoptera: Bruchidae). Proceedings of the 20th Iranian Plant Protection Congress; Plant Diseases, Weed Science, Entomology, Acarology and Zoology. 2012; Shiraz University, Shiraz, Iran. 259 p. 207. Jairoce CF, Teixeira CM, Nunes CFP, Nunes AM, Pereira CMP, Garcia FRM. Insecticide activity of clove essential oil on bean weevil and maize weevil. Rev Brasil Engenharia Agríc Ambiental. 2016; 20: 72-77. 208. Saleem M, D Hussain, RH Rashid, HM Saleem, G Ghouse, M Abbas. 2013. Insecticidal activities of two citrus oils against Tribolium castaneum (Herbst). Am J Res Comm. 1(6): 67-74. 209. Saleem S, ul Hasan M, Sagheer M, Sahi ST. Insecticidal activity of essential oils of four medicinal plants against different stored grain insect pests. Pakistan J Zool. 2014; 46(5): 1407-1414. 210. Chaubey MK. Insecticidal activities of Cinnamomum tamala (Lauraceae) essential oil against Sitophilus oryzae L. (Coleoptera: Curculionidae). Int J Entomol Res. 2016; 4(3): 91-98. 211. Tewari N, SN Tiwari SN. Fumigant toxicity of lemon grass, Cymbopogon flexuosus (D.C.) Stapf oil on progeny production of Rhyzopertha dominica F., Sitophilus oryzae L. and Tribolium castaneum Herbst. Environ Ecol. 2008; 26(4A): 1828-1830. 212. Ngomo AF, Ngamo LT, Tapondjou LA, Tchouanguep FM, Hance T. Insecticidal effects of the powdery formulation based on clay and essential oil from leaves of Clausena anisata (Willd) J.D. ex. Benth (Rutaceae) against Acanthoscelides obtectus (Say) Hook (Coleoptera; Bruchidae). J Pest Sci. 2008; 81(4); 227-234. 213. Pereira ACRL, Oliverira JV, Gondim Junior MGC, Cmara CAG. Insecticide activity of essential and fixed oils in Callosobruchus maculatus (Fabr. 1775) (Coleoptea: Bruchidae) in cowpea grains Vigna unguiculata (L.) Walp. Ciencia Agrotec. 2008; 32(3): 717-724. Chaubey Essential oils as green pesticides of stored grain insects 242 European Journal of Biological Research 2019; 9(4): 202-244 214. Bachrouch O, Ben Jemba JM, Wissem AW, Talou T, Marzouk B, Abderrab M. Composition and insecticidal activity of essential oil from Pistacia lentiscus L. against Ectomyelois ceratoniae Zeller and Ephestia kuehniella Zeller (Lepidoptera: Pyralidae). J. Stored Prod Res. 2010. 46: 242-247. 215. Klocke JA, Barnby MA. Plant allelochemicals as sources and models of insect control agents. Chung Yang Yen Chiv Yuan Chih Yen Chiu So Chuan K’an. 1989; 9: 455-465. 216. Obeng-Ofori D, Reichmuth C. Bioactivity of eugenol, a major component of essential oil of Ocimum suave (Wild.) against four species of stored-product Coleoptera. Int J Pest Manag. 1997; 43: 89-94. 217. Ketoh GK, Koumaglo HK, Glitho IA, Huignard J. Comparative effects of Cymbopogon schoenanthus essential oil and piperitone on Callosobruchus maculatus development. Fitoterapia. 2006; 77: 506-510. 218. Sanon A, Iboudo Z, Dabire CLB, Nebie RCH, Dicko IO, Monge JP. Effects of Hyptis spicigera Lam. (Labiatae) on the behaviour and development of Callosobruchus maculatus F. (Coleoptera: Bruchidae), a pest of stored cowpeas. Int J Pest Manag. 2006; 52(2): 117-123. 219. Isikber AA, Alma MH, Kanat M, Karci A. Fumigant toxicity of essential oils from Laurus nobilis and Rosmarinus officinalis against all the stages of Tribolium confusum. Phytoparasitica. 2006; 34(2): 167-177. 220. Sahaf BZ, Moharramipour S. Fumigant toxicity of Carum copticum and Vitex pseudo-negundo essential oils against eggs, larvae and adults of Callosobruchus maculatus. J Pest Sci. 2008; 81(4): 213-220. 221. Abbasipour H, Mahamoud M, Rastegar F, Hossinpour MH. Fumigant toxicity and oviposition deterrence of the essential oil from Cardamom, Elettaria cardamomum against three stored product insects. J Insect Sci. 2011; 11: 165-173. 222. Abbas SK, Ahmad F, Sagheer M, Mansoor-Ul-Hasan Y, Saeed A, Wali M. Insecticidal and growth inhibition activities of Citrus paradisi and Citrus reticulate essential oils against lesser grain borer, Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae). World J Zool. 2012; 7: 289-294. 223. Chaubey MK. Insecticidal effects of Allium sativum (Alliaceae) essential oil against Tribolium castaneum (Coleoptera: Tenebrionidae). J Biol Active Prod Nat. 2013; 3(4): 248-258. 224. Aboua LRN, Seri-Kouassi BP, Koua KK. Insecticidal activity of essential oils from three aromatic plants on Callosobruchus maculatus F. in Cote D’ivoire. Eur J Sci Res. 2010; 39: 234-250. 225. Lee S, Tsao R, Peterson C, Coats JR. Insecticidal activity of monoterpenoids to the western corn root worm (Coleoptera: Chrysomelidae), two spotted spider mite (Acari: Tetranychidae) and housefly (Diptera: Muscidae). J Econ Entomol. 1997; 90: 883-892. 226. Ryan ME, Byrne O. Plant insect coevolution and inhibition of acetylcholinesterase. J Chem Ecol. 1988; 14: 1965-1975. 227. Re L, Barocci S, Sonnino S, Mencarelli A, Vivani C, Paolucci G, Scarpantonio A, Rinaldi L, Mosca E. Linalool modifies the nicotinic receptor-ion channel kinetics at the mouse neuromuscular function. Pharmacol Res. 2000; 42: 177-181. 228. Evans PD. Biogenic amines in the insect nervous system. Adv Insect Physiol. 1980; 15: 317- 473. 229. Hollingworth RM, Johnstone EM, Wright N. In: Magee PS, Kohn GK, Menn JJ, eds Pesticide synthesis through Rational Approaches, ACS Symposium Series No. 255: 103-125. 1984; Am. Chem. Soc. Washington, DC. 230. Evans PD. Multiple receptor types for octopamine in the locust. J Physiol London. 1981; 318: 99-122. 231. Enan E, Beigler M, Kende A. Insecticidal action of terpenes and phenols to cockroaches: effect on octopamine receptors. Paper presented at the Intern. 1998; Symp. Plant Prot Belgium. 232. Enan E. Insecticidal activities of essential oils: Octopaminergic sites of action. Comp Biochem Physiol Part C. 2001; 130: 325-337. Chaubey Essential oils as green pesticides of stored grain insects 243 European Journal of Biological Research 2019; 9(4): 202-244 233. Ahmed KS, Yosui Y, Lachikawa T. Effect of neem oil on mating and oviposition behavior of azuki bean weevil, Callosobrucus Chinensis L. (Coleoptera: Bruchidae). Pakistan J Biol Sci. 2001; 4(11): 1371-1373. 234. Emekci M, Navarro S, Donahaye E, Rindner M, Azrieli A. Respiration of Rhyzopertha dominica (F.) at reduced oxygen concentration. J Stored Prod Res. 2004; 40: 27-38. 235. Isman MB. Botanical insecticides: From richer for poorer. Pest Manag Sci. 2008; 64(1): 8-11. 236. Gillij YG, Gleiser RM, Zygadlo JA. Mosquito repellent activity of essential oils of aromatic plants growing in Argentina. Biores Technol. 2008; 99: 2507-2515. 237. Berenbaum M. Allelochemical interactions in plants. Rec Adv Phytochem. 1985; 19: 139-169. 238. Youssef NS. Toxic and synergistic properties of several volatile oils against larvae of the house fly, Musca domestica vicina Maquart (Diptera; Muscidae). Egypt German Soc Zool. 1997; 22: 131-149. 239. Kumbhar PP, Dewang PM. Monoterpenoids: The natural pest management agents. Frag Flav Assoc India. 2001; 3: 49-56. 240. Tripathi AK, Upadhyay S, Bhuiyan M, Bhattacharya PR. A review on prospects of essential oils as biopesticides in insect pest management. J Pharmacog Phytother. 2009; 1: 52-63. 241. Isman MB, Miresmailli S, Machial C. Commercial opportunities for pesticides based on plant essential oils in agriculture, industry and consumer products. Phytochem Rev. 2011; 10: 197-204. 242. Anderson IB, Mullen WH, Meeker JE, Khojasteh-Bakht SC, Oishi S, Nelson SD, Blanc PD. Pennyroyal toxicity: Measurement of toxic metabolite levels in two cases and review of the literature. Ann Internal Med. 1996; 124: 726-734. 243. Hold KM, Sirisoma NS, Ikeda T, Narahashi T, Casida JE. Thujone (the active component of absinthe): γ- Aminobutyric acid type A receptor modulation andmetabolic detoxification. Proc Natl Acad Sci USA. 2000; 3826-3831. 244. Carson CF, Mee BJ, Riley TV. Mechanism of action of Melaleuca alternifolia (tea tree) oil on Staphylococcus aureus determined by time kill, lysis, leakage and salt tolerance assays and electron microscopy. Antimicrob Agents Chemother. 2002; 46: 1914-1920. 245. Novgorodov SA, Gudz TI. Permeability transition pore of the inner mitochondrial membrane can operate in two open states with different selectivities. J Bioenerg Biomembr. 1996; 28: 139-146. 246. Vercesi AE, Kowaltowski AJ, Grijalba MT, Meinicke AR, Castilho RF. The role of reactive oxygen species in mitochondrial permeability transition. Biosci Rep. 1997; 17: 43-52. 247. Yoon HS, Moon SC, Kim ND, Park BS, Jeong MH, Yoo YH. Genistein induces apoptosis of RPE-J cells by opening mitochondrial PTP. Biochem Biophys Res Commun. 2000; 276: 151-156. 248. Armstrong JS. Mitochondrial membrane permeabilization: the sine qua non for cell death. BioEssays. 2006; 28: 253-260. 249. Guba R. Toxicity myths-essential oils and their carcinogenic potential. Int J Aromather. 2001; 11: 76-83. 250. Miller EC, Swanson AB, Philips DH, Fletcher TL, Liem A, Miller JA. Structure-sctivity studies of the carcinogenecities in the mouse and rat of some naturally occurring and synthetic derivatives related to safrole and estragole. Cancer Res. 1983; 43: 1124-1134. 251. Anthony A, Caldwell G, Hutt AG, Smith RL. Metabolism of estragole in rat and mouse and influence of dose size on excretion of the proximate carcinogen 10-hydroxyestragole. Food Chem Toxicol. 1987; 25: 799-806. 252. Averbeck D, Averbeck S. DNA photodamage, repair, gene induction and genotoxicity following exposures to 254 nm UV and 8-methoxypsoralen plus UVA in a eukaryotic cell system. Photochem Photobiol. 1998; 68: 289-295. Chaubey Essential oils as green pesticides of stored grain insects 244 European Journal of Biological Research 2019; 9(4): 202-244 253. Zhou MZ, Sun HC, Hu ZH, Sun XL. SOD enhances infectivity of Helocoverpa armigera single nucleocapsid nucleopolyhedrosis against H. armigera larvae. Virologia Sinica. 2004; 18: 506-507. 254. Burkey JL, Sauer JM, McQueen CA, Sipes IG. Cytotoxicity and genotoxicity of methyleugenol and related congeners - a mechanism of activation for methyleugenol. Mutat Res. 2000; 453: 25-33. 255. EPA. Flower and vegetable oils. Prevention, pesticides, and toxic substances (7508W). 1993; EPA-738-F- 93-027. www.epa.gov/oppsrrd1/REDs/factsheets/4097fact.pdf. 256. Isman MB, Miresmailli S, Machial C. Commercial opportunities for pesticides based on plant essential oils in agriculture, industry and consumer products. Phytochem Rev. 2011; 10: 197-204. 257. Isman MB. Botanical insecticides, deterrents and repellents in modern agriculture and an increasing regulated world. Annu Rev Entomol. 2006; 52: 45-66. 258. Marrio DLM, Giovanni S, Stefania D, Emanela B. Essential oil formulations useful as a new tool for insect pest control. AAPS Pharmscitech. 2002; 3: 64-74. 259. Martn A, Varona S, Navarrete A, Cocero MJ. Encapsulation and co-precipitation processes with supercritical fluids: Applications with essential oils. Open Chem Eng J. 2010; 4: 31-41. 260. Yang FL, Li XG, Zhu F, Lei CL. Structural characterization of nanoparticles loaded with garlic essential oil and their insecticidal activity against Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae). J Agric Food Chem. 2009; 10156-10162. 261. Anjali CH, Khan SS, Margulis-Goshen K, Magdassi S, Chandrasekaran N. Formulation of water- dispersible anopermethrin for larvicidal applications. Ecotoxicol Environ Saf. 2010; 73: 1932-1936. 262. Vinutha JS, Bhagat D, Bakthavatsalam N. Nanotechnology in the management of polyphagous pest Helicoverpa armigera. J Acad Indus Res. 2013; 1: 606-608. 263. Heinmenberg H. Project XP-11, 1992; Patent CA 92-20 77284920901. 264. Kono M, Ono M, Ogata K, Fujimori M, Imai T, Tsucha S. Fuji Flavor Co, Japan & Nippon Tobacco Sangyo. Control of insects with plant essential oils and insecticides. 1993; Patent JP 93-70745 930308. 265. Matsumoto T, Takaoka K, Watanabe C. Acaricides, insecticides and insect repellents containing benzaldehyde or perilla aldehyde. 1987; Patent JP-87 176437 870715. 266. Riedel G, Heller G, Voigt M. Detia Freyberg GmbH, Germany (Federal Republic). Citronellol and eugenol as mothproofing agents. 1989; Patent DE 89-3901341 890118. 267. Sano J, Une T. Kanebo Ltd., Japan. Washfast insectresistant fabrics. 1993; Patent JP 93-37412 930201. 268. Feliu Zamora M. Anfel SA, Spain. Manufacture of insecticidal coating materials. 1989; Patent ES 90-1212 900427. 269. Yamaguchi A, Okubo T, Nanbu H, Ishigaki S, Kawetake M, Okabe T, Saito K, Otomo Y. Taiyo Chemical Company Ltd. Japan. Insect repelling and antibacterial effect adhesive. 1989; Patent JP 89-248713 890925. 270. Urabe C. Insect control in wood. 1992; Patent JP 92-308238 921021.