jear2012 [Journal of Entomological and Acarological Research 2014; 46:715] [page 13] Efficiency of Mentha piperita L. and Mentha pulegium L. essential oils on nutritional indices of Plodia interpunctella Hübner (Lepidoptera: Pyralidae) K. Saeidi, B. Hassanpour Department of Entomology, Agricultural and Natural Resources Research Center, Yasouj, Iran Abstract Antifeedant activity of plant extracts from Mentha piperita L. and Mentha pulegium L. were tested against the Indian meal moth, Plodia interpunctella (Hübner). The nutritional indices: relative growth rate (RGR), relative consumption rate (RCR), efficiency of conversion of ingested food (ECI) and feeding deterrence index (FDI) were meas- ured for first-instar larvae (15-d old). Treatments were evaluated using a flour disk bioassay in the dark, at 25±1°C and 60±5% R.H. Concentrations of 0, 0.1, 0.5, 0.75, 1, 1.5 and 2 mL/disk were prepared from each essential oil. After 72 h, nutritional indices were calculated. M. piperita oils were more effective than M. pulegium oils, by signifi- cantly decreasing the RGR, RCR and FDI. At the highest concentration tested (2 mL/disk), the ECI (9%) was significantly reduced. Introduction Stored cereals, oilseeds, pulses, spices, dried fruits, tree nuts and their processed foods are important for food and trade purposes and suffer economic and quality losses due to insect pests (Lamiri et al., 2001; Passino et al., 2004; Tapondjou et al., 2005; Ali & Rizvi, 2008). There are over 600 species of beetle pests and 70 species of moths capable of causing quantitative and qualitative losses (Rajendran, 2002). In developing countries, damage is between 10 to 40% (Shaaya et al., 1997). In some rural areas of Iran that use traditional storages, damage caused by stored product insects can be as high as 80% (Modarres-Najafabadi et al., 2006). P. interpunctella (Hübner) (Indian meal moth) is considered to be the most troublesome of the moths infesting stored products in the world (Phillips et al., 2000; Mohandass et al., 2007). It attacks all cereal prod- ucts, whole grains, dried fruits, pet foods, birdseed, dried milk and nuts (Arthur et al., 1991). The larvae are generalists, as they can feed on grain products, seeds, dried fruit, dog food, and spices (Arthur et al., 1990; Mohandass et al., 2007). Damage is caused by the larvae spinning silken threads as they feed and crawl, thus webbing the particles of food together (Simmons & Nelson, 1975). The control of this pest in storage systems mainly depends on fumigants such as methyl bromide or phos- phine, and fogging with pyrethrins or dichlorvos. However, methyl bro- mide was banned in many countries starting in 2004, because of its ozone-depleting properties (Hansen & Jensen, 2002). Synthetic pesticides have been considered the most effective and accessible means of controlling insect pests of stored products (Huang & Subramanyam, 2005). These chemicals are associated with undesir- able effects on the environment due to their slow biodegradation and some toxic residues in products, affecting mammalian health (Benhalima et al., 2004; Isman, 2006; Halder et al., 2010). The adverse effects of synthetic pesticides have amplified the need for an effective and biodegradable pesticide. Natural products are an excellent alternative to synthetic pesticides as a means to reduce negative impacts on human health and the envi- ronment. Among the various kinds of natural substances that have received particular attention as natural agents for insect management are essential oils from aromatic plants. Essential oils are renewable, non-persistent in the environment and relatively safe to natural ene- mies, non-target organisms and human beings (Halder et al., 2010). Essential oils are defined as any volatile oil(s) that have strong aro- matic components and that give a distinctive odor, flavor or scent to a plant. These are the by-products of plant metabolism and are common- ly referred to as volatile plant secondary metabolites (Koul et al., 2008). Because of the intensity of plant-insect interactions, the plants have well-developed defense mechanisms against pests and are excellent sources of new insecticidal substances. Their components and quality vary with geographical distribution, time of harvest, growing condi- tions and method of extraction (Yang & Zheng, 2005). Effects of essen- tial oils on stored-product insect pests have been reported on exten- sively (Ogendo et al., 2008; Park et al., 2008; Benzi et al., 2009; Ayvaz et al., 2010; Nayamador et al., 2010; Taghizadeh et al., 2010). The insecticidal activity of some essential oils from Lamiaceae has been evaluated against a number of stored product insects. For exam- ple, Mollai et al. (2010) found strong insecticidal activity of essential oil from Satureja hortensis (Lamiaceae) on P. interpunctella. The 24-h LC50 values against adults were 140 mL/L air. In another experiment, Aliakbari et al. (2010) studied insecticidal activity of the essential oil from Thymus daenensis (Lamiaceae) on Tribolium confusum (Tenebrionidae). Mortality was evaluated after 24 and 48 h. LC50 and Correspondence: Karim Saeidi, Department of Entomology, Agricultural and Natural Resources Research Center, P.O. Box 351, Yasouj, Iran. Tel.: +98.741.3334821 / +98.741.3334821 - Fax: +98.741.3334011. E-mail: saeidi391@yahoo.com Key words: essential oil, nutritional indices, Plodia interpunctella. Received for publication: 3 December 2012. Revision received: 31 July 2013. Accepted for publication: 7 August 2013. ©Copyright K. Saeidi and B. Hassanpour, 2014 Licensee PAGEPress, Italy Journal of Entomological and Acarological Research 2014; 46:715 doi:10.4081/jear.2014.715 This article is distributed under the terms of the Creative Commons Attribution Noncommercial License (by-nc 3.0) which permits any noncom- mercial use, distribution, and reproduction in any medium, provided the orig- inal author(s) and source are credited. Journal of Entomological and Acarological Research 2012; volume 44:eJournal of Entomological and Acarological Research 2014; volume 46:715 No n- co mm er cia l u se on ly [page 14] [Journal of Entomological and Acarological Research 2014; 46:715] LC95 values were 50 and 169 mL after 24-h and 42 and 103 mL after 48 h, respectively. Ebadollahi & Mahboubi (2011) studied fumigant activ- ity of the essential oil from Lavandula stoechas L. (Lamiaceae) on Tribolium castaneum. Based on the results of this research, essential oils of L. stoechas should be considered as a potential control agent against T. castaneum. Rafiei-Karahroodi et al. (2009) studied the effect of essential oils from Dracocephalum moldavica, Lavandula officinalis, Melissa officinalis and Rosmarinus officinalis on 1-d and 3-d-old eggs of P. interpunctella. Results indicated that M. officinalis and R. officinalis are suitable candidates for replacing synthetic pesticides in warehous- es to control P. interpunctella. The main goal of the present study was to evaluate the insecticidal activities of essential oils from M. piperita and M. pulegium grown in Iran for the control of P. interpunctella. Materials and methods Moth culture The Indian meal moths, based on described by Silhacek & Miller (1972), were reared on artificial diet containing: cornmeal (26%), whole wheat flour (23%), glycerol (16%) honey (14%), ground dog meal (10%), brewers’ yeast (5%), rolled oats (4%) and wheat germ (2%) in a cham- ber set to a light:dark period of (11:13) and a temperature of 28±2°C. Collected and dried plant specimens Two plants known to have medicinal activity, M. piperita L. and M. pulegium L., were collected from their natural habitats, from different localities in Iran. The identity of each plant species was verified by En. Shahabedin Mirinejad (botanical specialist from Agriculture and Natural Resources Researches Center of Kohgiloyeh and Boyerahmad, Yasouj), using live specimens and photographs. Extraction of essential oils Plant materials were air dried in the shade at room temperature (26- 28°C) for 20 d and stored in darkness until distillation. The essential oils were isolated from dried plant samples by hydro-distillation using a Clevenger apparatus. Conditions of extraction were: 50 g of air-dried sample, 1:10 plant material/water volume ratio, 3 h distillation. The essential oils were collected, dried over anhydrous sodium sulfate and stored at 4°C until use. Flour disk bioassay According to the method of Mohandass et al. (2007) a suspension of 10 g wheat flour in 50 mL distilled water was prepared. A micropipette was used to transfer 200-mL aliquots from the suspension onto a plas- tic sheet. After 4 h at room temperature, the wheat flour suspensions in the form of spherical disks were transferred to a petri dish. Prepared disks were kept for 12 h to dry inside an oven, after which the weight of the flour disks was between 35-45 mg and their moisture content was approximately 15%. Different concentrations of essential oils from M. piperita and M. pulegium (0.1, 0.5, 0.75, 1, 1.5 and 2 mL in 1 mL of acetone) were placed on each disk separately and held for 20 min at room temperature to allow for evaporation of the acetone. In each petri dish, one flour disk was placed along with 10 first- instar Indian meal moth larvae and held at 25±1°C and 60±5% R.H. for 3 d. At the begin- ning of the experiment, the weight of flour disks and larvae was meas- ured. After 3 d, flour disks and larvae were weighed again and the num- ber of dead larvae noted. There were 5 replicates. Nutritional indices Nutritional indices were calculated according to Tripathi et al. (2002), with some modifications: Relative Growth Rate (RGR)=(A-B)/(B×Day) (1) where A=weight of live insects (mg) on the third day/number of live insects on the third day; B=original weight of insects (mg)/original number of insects. Relative Consumption Rate (RCR)=D/(B×day) (2) where D=biomass ingested (mg)/number of live insects on the third day. Percentage efficacy of conversion of ingested food (ECI)=RGR/RCR ×100. The feeding deterrent activity was calculated as a feeding deter- rent index (Isman, 2006): (% FDI)=[(C–T)/C]×100 (3) where C is the weight consumption of food in the control and T is the weight consumption food in the treatment. Data analysis Each of the indices was calculated using a completely randomized factorial design, and five replicates were performed. The first factor in this design included three treatments, consisting of the essential oils of M. piperita, M. pulegium and a control, and the second factor consist- ed of six concentrations of plant essential oils: 0.1, 0.5, 0.75, 1, 1.5 and 2 mL/disk, and a control treatment. Before statistical analysis, the ECI and FDI nutritional indices data were normalized using an Arcsin√X/100 transformation. The means were separated using Duncan’s multiple range test at the 5% significance level. Results Plant source and dose significantly affected all nutritional indices (Table 1). For RCR, ECI and FDI there was a significant interaction Article Table 1. Analysis of variance of essential oils of Mentha piperita and Mentha pulegium on nutritional indices of larvae of Plodia inter- punctella. Source of variation Degrees of freedom Mean squares RGR RCR ECI FDI Plant 1 7.01×10–4* 0.066** 99.836** 5167.934** Concentration 6 0.002** 0.032** 26.125** 1998.654** Plant×Concentration 6 3.086×10–5ns 0.003** 16.822** 176.234** Error 42 2.620×10–5 3.736 4.354 0.023 RGR, relative growth rate; RCR, relative consumption rate; ECI, efficiency of conversion of ingested food; FDI, feeding deterrence index; ns, non-significant; *, ** respectively significant differences at 5 and 1% level. No n- co mm er cia l u se on ly [Journal of Entomological and Acarological Research 2014; 46:715] [page 15] Article Table 3. Total average effect of essential oils of Mentha piperita and Mentha pulegium at various concentrations on nutritional indices of larvae of Plodia interpunctella. Concentration (mL/disk) Standard error±average nutritional indices RGR (mg/mg/day) RCR (mg/mg/day) ECI% FDI% 0.00 (Control) 0.051±0.001a 0.3131±0.015a 16.288±0.453a - 0.1 0.035±0.001b 0.253±0.014b 13.833±0.765a 13.281±2.050f 0.5 0.031±0.001bc 0.230±0.017c 13.478±0.749ab 20.098±2.710e 0.75 0.027±0.000c 0.210±0.015d 12.857±0.512abc 25.889±3.112d 1 0.019±0.002d 0.169±0.016e 11.242±0.765abc 32.705±3.256c 1.5 0.016±0.001d 0.116±0.023f 13.793±1.682cb 48.949±6.014b 2 0.010±0.003e 0.102±0.039g 9.384±1.812c 52.829±5.235a RGR, relative growth rate; RCR, relative consumption rate; ECI, efficiency of conversion of ingested food; FDI, feeding deterrence index. a,b,c,d,e,f,gDissimilar letters in each column with using Duncan’s test at level of 1% together have significant differences. Table 2. Effect of essential oils of Mentha piperita and Mentha pulegium on nutritional indices of larvae of Plodia interpunctella. Essential oil RGR (mg/mg/day) RCR (mg/mg/day) ECI% FDI% Mentha piperita 0.026±0.002b 0.219±0.160b 11.94±0.76a 34.9±3.8a Mentha pulegium 0.028±0.001a 0.294±0.006a 9.64±0.44b 14.2±2.2b RGR, relative growth rate; RCR, relative consumption rate; ECI, efficiency of conversion of ingested food; FDI, feeding deterrence index. a,bValues in the same column followed by different letters are significantly different (P<0.01, Duncan’s multiple range test). Figure 1. Effect of essential oil Mentha piperita and Mentha pulegium at various concentrations on nutritional indices larvae of Plodia interpunctella. No n- co mm er cia l u se on ly [page 16] [Journal of Entomological and Acarological Research 2014; 46:715] between plant source and dose, indicating that the effect of plant source varied significantly with dose (Table 1). Essential oils of M. piperita had a significantly greater negative impact on nutritional indices than did the essential oils of M. pulegium (Tables 2 and 3). However, these differences were small (Figure 1). Discussion and conclusions In this study, to compare the anti-nutritional effects of essential oils of M. piperita and M. pulegium, parameters as indicators of nutrition were used by employing no-choice tests of the insects’ food, which had been impregnated with various concentrations of the essential oils. In these experiments, two primary outcomes were measured. The first was weight loss of the insects compared with the control during the duration of this experiment, expressed as the RGR index. Second, the RCR index was measured and compared with control insects to meas- ure whether test insects had taken less or avoided eating treated food. The effective weight loss could be related to the impact of essential oils on insect food (Koul et al., 2008), and to clarify avoidance of insect feeding, FDI was used. In this experiment, it was observed that increas- ing the concentration and changing the type of essential oil reduced the RGR and RCR values, so that there was a greater effect with essen- tial oil at high concentrations, and regarding essential oil type, M. piperita was found to be more effective. In terms of the mechanism of action in response to this decrease, it is clear that low concentrations of essential oils of M. piperita and M. pulegium did not show significant differences in terms of ECI, but with very high essential oil concentra- tions, the value of the ECI was reduced. Even at lower concentrations of the essential oils of M. piperita and M. pulegium, there was signifi- cant inhibition of insect feeding. Therefore, the impact on the RGR and RCR can be attributed to the effects of feeding deterrence or FDI. Even at lower concentrations, these essential oils can effectively reduce insect feeding, as noted in the studies of other researchers. In this study, to examine the anti-nutritional properties of mint essential oils, Indian meal moth was used as a model, and showed that sub-lethal concentrations of essential oils in warehouse use could pre- vent the insects from feeding on the stored product. Therefore, we would conclude that a method to combine these essential oils with some storage products could be effective in controlling pests. References ALI A., RIZVI P.O., 2008. - Bio-efficacy of some plant leaf extracts against mustard aphid, Lipaphis erysimikalt on Indian mustard, Brassica juncea. - J. Plant. Protec. Res. 50: 2. ALIAKBARI J., FALLAHZADEH M., GHASEMI A., ABDIZADEH R., 2010. - Insecticidal activity of essential oil from Thymus daenensis Celak against Tribolium confusum Dur. Proc. 19th Iranian Plant Protection Congress, July 31-August 3, 2010. - Iranian Research Institute of Plant Protection, Tehran, Iran. ARTHUR F.H., HIGHLAND H.A., MULLEN M.A., 1991. - Efficiency and longevity of two commercial sex pheromone lures for Indian meal moth and almond moth (Lepidoptera: Pyralidae). - J. Econ. Entomol. 26: 64-68. ARTHUR F.H., SIMONAITIS R.A., THRONE J.E., ZEHNER J.M., 1990. - Evaluation of chlorpyrifos-methyl and chlorpyriphos-methyl plus methoprene as protectants of stored corn: small bin tests. - J. Econ. Entomol. 83: 1114-1121. AYVAZ A., SAGDIC O., KARABORKLUS., OZTURK I., 2010. - Insecticidal activity of the essential oils from different plants against three stored-product insects. - J. Ins. Sci. 10: 21.1-21.13. BENHALIMA H., CHAUDHRY M.Q., MILLS K.A., PRICE N.R., 2004. - Phosphine resistance in stored-product insects collected from var- ious grain storage facilities in Morocco. - J. Stored Prod. Res. 40: 241-249. BENZI V., STEFANAZZI N., FERRERO A., 2009. - 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. Sci. 69: 154-159. EBADOLLAHI A., MAHBOUBI M., 2011. - Insecticidal activity of essen- tial oil isolated from Azilia eryngioides (Pau) Hedge Et Lamond against two beetle pests. - Chilean J. Agri. Res. 71: 406-411. HALDER J., SRIVASTAVA C., DUREJA P., 2010. - Effect of methanolic extracts of periwinkle (Vinca rosea) and bottlebrush (Callistemon lanceolatus) alone and their mixtures against neonate larvae of gram pod borer (Helicoverpa armigera). - Indian J. Agri. Sci. 80: 820-823. HANSEN L.S., JENSEN K.M.W., 2002. - Effect of temperature on para- sitism and host-feeding of Trichogramma turkestanica (Hymenoptera: Trichogrammatidae) on Ephestia kuhniella (Lepidoptera: Pyralidae). - J. Econ. Entomol. 95: 50-56. HUANG F., SUBRAMANYAM B., 2005. - Management of five stored-prod- uct insects in wheat with pirimiphosmethyl and pirimiphos-methyl plus synergized pyrethrins. - Pest Manag. Sci. 61: 356-362. ISMAN M.B., 2006. - Botanical insecticide deterrents in modern agricul- ture and increasingly regulated world. - Annu. Rev. Entomol. 5: 45-66. KOUL P., WALLA S., DHALIWAL G.S., 2008. - Essential oils as green pes- ticides. Potential and constraints. Biopestic. Int. 4: 63-83. LAMIRI A., LHALOUI S., BENJILALI B., BERRADA M., 2001. - Insecticidal effects of essential oils against Hessian fly, Mayetiola destructor (Say). - Field Crop Res. 71: 9-15. MODARRES-NAJAFABADI S.S., FANI H.R., GHOLAMIAN G.H., 2006. - Study on eucalyptus product uses (seed and leaf powder) on stored product pests of wheat and barley in Sistan region-Iran. - Iran. J. Med. Aromat. Plant. 22: 117-127. MOHANDASS S., ARTHUR F.H., ZHU K.Y., THRONE J.E., 2007. - Biology and management of Plodia interpunctella (Lepidoptera: Pyralidae) in stored products. - J. Stored Prod. Res. 43: 302-311. MOLLAI M., IZADI H., DASHTI H., AZIZI M., RAHIMI H., 2010. - Fumigant toxicity of essential oils from Satureja hortensis and Zingiber officinalis on Plodia interpunctella. Proc. 19th Iranian Plant Protection Congress, July 31-August 3, 2010. - Iranian Research Institute of Plant Protection, Tehran, Iran. NAYAMADOR W.S., KETOH G.K., AMEVOIN K., NUTO Y., KOUMAGLO H.K., GLITHO I.A., 2010. - Variation in the susceptibility of two Callosobruchus species to essential oils. - J. Stored Prod. Res. 46: 48-51. OGENDO J.O., KOSTYUKOVSKY M., RAVID U., MATASYOH J.C., DENG A.L., OMOLO E.O., KARIUKI S.T., SHAAYA E., 2008. - Bioactivity of Ocimum gratissimum L. oil and two of its constituents against five insects attacking stored food products. - J. Stored Prod. Res. 44: 328-334. PARK I.K., KIM J.N., LEE Y.S., LEE S.G., YOUNG J., AHN, Y.A., SHIN S.C., 2008. -Toxicity of plant essential oils and their components against Lycoriella ingenua (Diptera: Sciaridae). - J. Econ. Entomol. 101: 139-144. PASSINO G.S., BAZZONI E., MORETTI M., 2004. - Microencapsulation essential oils active against Indian meal moth. - Bol. Sanidad Vegetal Plagas 30: 123-130. PHILLIPS T.W., BERBERT R.C., CUPERUS G.W., 2000. - Post-harvest integrated pest management. In: FRANCIS, F.J. (Ed.), Encyclopedia of food science and technology. 2nd ed. - Wiley Inc., New York: 2690-2701. RAFIEI-KARAHROODI Z., MOHARAMIPOUR S., FARAZMAND H., Article No n- co mm er cia l u se on ly KARIMZADEH-ESFAHANI J., 2009. - Effect of eighteen plant essen- tial oils on nutritional indices of larvae Plodia interpunctella Hubner (Lepidoptera: Pyralidae). - J. Entomol. Res. 1: 209-219. RAJENDRAN S., 2002. - Postharvest pest losses. In: Pimentel, D. (Ed.), Encyclopedia of pest management. - Marcel Dekker, Inc., New York: 654-656. SHAAYA E., KOSTJUKOVSKI M., EILBERG J., SUKPRAKARN C., 1997. - Plant oils as fumigants and contact insecticides for the control of stored-product insects. - J. Stored Prod. Res. 33: 7-15. SILHACEK D.L., MILLER G.L., 1972. - Growth and development of the Indian meal moth, Plodia interpunctella Hubner (Lepidoptera: Pyralidae) under laboratory mass-rearing conditions. - Ann. Entomol. Soc. Am. 65: 1084-1087. SIMMONS P., NELSON H.D., 1975. - Insects on dried fruits. USDA Agricultural Handbook no. 464. - USDA, Washington DC, USA. TAGHIZADEH V., SAROUKOLAHI A., MOHARRAMIPOUR S., MESHKATALSADAT M.H., 2010. - Insecticidal properties of Thymus persicus essential oil against Tribolium castaneum and Sitophilus oryzae. - J. Pest. Sci. 83:3-8. TAPONDJOU AL., ADLERB C., FONTEM DA, BOUDAA H., REICHMUTHB C., 2005. - Bioactivity of cymol and essential oils of Cupressus sem- pervirens and Eucalyptus saligna against Sitophilus zeamais and Tribolium confusum. - J. Stored Products Res. 41: 91-102. TRIPATHI A.K., PRAJAPATI V., AGGARWAL K.K., KUMAR S., 2002. - Bioactivity of I-carvone, d-carvone and dihydrocarvone towards three stored product beetles. - J. Econ. Entomol. 96: 1594-1607. YANG P.Y., ZHENG S., 2005. - Adulticidal activity of five essential oils against Culex pipiens quinquetasciatus. - J. Pestic. Sci. 30: 84-89. [Journal of Entomological and Acarological Research 2014; 46:715] [page 17] Article No n- co mm er cia l u se on ly