146 1. Introduction The potato tuber moth, Phthorimaea operculella (Zeller) is a widely distributed oligophagous pest of so- lanaceous crops, including potato, tomato, tobacco, and other cultivated or uncultivated Solanaceae (Cameron et al., 2002). Due to the economically important damage it causes, this pest has a long history of exposure to a broad array of synthetic insecticides. Not surprisingly, P. oper- culella has developed resistance to many of these insec- ticides, including chlorinated hydrocarbons, organophos- phates, carbamates, and pyrethroids (Dillard et al., 1993; Symington, 2003). In the past decade, several classes of conventional in- secticides have emerged that show great promise for con- trolling P. operculella (Edomwande et al., 2000; Saour, 2008; Clough et al., 2010). Spinosad is a naturally-derived biorational insecticide with a relatively benign toxicol- ogy profile (Aydin and Gürkan, 2005). It is comprised primarily of two macrocyclic lactones, spinosyn A and D, secondary metabolites produced by the actinomycete, Saccharopolyspora spinosa, under natural fermentation conditions (Thompson et al., 2000). Insects ingesting spi- nosad experience paralysis caused by rapid excitation of the nervous system through binding to the nicotinic acetyl- choline and/or gamma-aminobutyric acid (GABA) recep- tors (Salgado, 1998). Currently, spinosad is registered in over 60 countries and is used to control Lepidoptera pests in many vegetables, fruits, and field crops (Legocki et al., 2010; Wang et al., 2013). Emamectin benzoate (an epi-methyl amino derivative of abamectin) is a second-generation avermectin analog with exceptional activity against lepidopterous on a va- riety of vegetable crops worldwide (Ioriatti et al., 2009). Avermectins (a 16-membered family) are naturally oc- curring macrocyclic lactones isolated from fermentation products of the soil micro-organism Streptomyces aver- mitilis (Ishaaya et al., 2002). Emamectin benzoate causes irreversible activation of chloride channels in the nervous system of insects. Shortly after contact or feeding expo- sure, the insect larvae stop feeding, become irreversibly paralyzed and die in three to four days. Due to its rapid photodegradation by sunlight, contact activity of emamec- tin benzoate against insect predators or parasites is limited to a very short period, allowing selective control of some Lepidoptera pests (Sechser et al., 2003). Chromafenozide is a relatively novel insecticide against lepidopteran larvae characterized by a methyl- chromane moiety in its dibenzoylhydrazine structure. Its mechanism of action is similar to nonsteroidal ecdysone agonists known as an insect-specific ecdysis hormone (Nakagawa, 2005). Although this compound is very toxic to insects, it is safe for mammals and is environmentally benign (European Food Safety Authority, 2013). Chro- mafenozide on plants is ingested orally by insect larvae to exhibit an ecdysis-promoting activity and lead to death. It is effective in controlling various lepidopterous pests Biorational insecticides against the potato tuber moth (Lepidoptera: Gelechiidae) on stored potatoes G. Saour, H. Ismail, I. Jassem, S. Tamer Department of Biotechnology, Atomic Energy Commission of Syria, PO Box 6091, Damascus, Syria. Key words: larvicidal, ovicidal, Phthorimaea operculella, potato storage, reduced-risk insecticides. Abstract: This study was conducted to evaluate the residual activity and efficacy of spinosad, emamectin benzoate, and chromafenozide on potato tuber moth, Phthorimaea operculella. Almost 0% egg hatch of 1-1.5 and 4-4.5-day-old eggs oc- curred when eggs were treated topically with spinosad at a concentration of 216 mg/L. No ovicidal activity was observed when emamectin benzoate and chromafenozide were tested against the eggs at concentrations of 5, 10, 15 and 37.5, 75 mg/L. Spinosad and emamectin benzoate were equally highly toxic to larvae (100% mortality) even when they were used at low rates. A relatively small proportion of F1 adults (≈11 to 20%) emerged in the chromafenozide treatment at concentrations of 37.5 and 75 mg/L. One hundred percent larval mortality was noted when potato tubers were sprayed with spinosad and emamectin benzoate and stored for at least 90 days after application. Whereas, chromafenozide applied at 75 mg/L was effective in reducing moth emergence, exhibiting activity for 14 days only after application; thereafter a similar number of F1 adults occurred in chromafenozide and control treatments. Thus, spinosad and emamectin benzoate could be used to ef- ficiently protect potato tubers from P. operculella infestation for three months in unrefrigerated rustic potato stores. Adv. Hort. Sci., 2014 28(3): 146-152 (1) Corresponding author: ascientific@aec.org.sy Received for publication 19 June 2014 Accepted for publication 13 November 2014 147 (i.e. Tortricidae, Pyralidae, Noctuidae) on vegetables or other agricultural plants (Yanagi et al., 2006). In reviewing the literature, no experimental data were found related to the direct contact or residual activity of these insecticides against P. operculella under storage conditions. Thus, the current study was performed to de- termine the potential effects of three insecticides - spi- nosad, emamectin benzoate, and chromafenozide - on the embryonic and early larval stages of the potato tuber moth. Moreover, this study was designed to evaluate the residual activity of the insecticides tested at various intervals up to 90 days after application. 2. Materials and Methods Insects Insects used in the experiments were obtained from a laboratory stock culture, which is supplemented each year with field-collected P. operculella larvae (infested tubers). Larvae were reared on wax-coated potato slices placed in plastic containers (40x25x10 cm). The newly emerged moths were collected and confined in 800 ml transparent plastic jars (10-12 pairs in each jar). A band of filter paper was added to the bottom of each jar for oviposition and 10% sucrose solution was presented as a food source. The rearing procedures were conducted at a constant tempera- ture of 25±1°C with 70±5% relative humidity (RH) and a photoperiod of 12:12 h (L:D). Insecticides The commercially formulated insecticides used in the present study were spinosad (Spintor® 2 SC, 240 mg [AI]/ ml), emamectin benzoate (Proclaim® 05 SG, 50 g [AI]/kg), and chromafenozide (Matric® 5% SC, 50 g [AI]/l). Ovicidal effect After the copulation and oviposition period, the first batch of eggs deposited on the oviposition support (white filter paper) from each pair were removed, counted and approximately divided into two groups. The eggs were counted with the aid of a binocular stereo microscope (Kyowa Optical SDZ-PL, Japan). The first group was used for insecticide treatments and the second served as a control. Eggs were kept in a small transparent plastic box (4x3x2 cm) and held at a constant temperature of 25±1°C with 70±5% RH, until used. Treatments were prepared by diluting each commercial formulation of the aforementioned insecticides in 1 L wa- ter. P. operculella eggs aged 1-1.5 and 4-4.5 days deposit- ed on the oviposition support were dipped for 30 s in three different concentrations 72, 144, 216 ml/L and 5, 10, 15 mg/L for spinosad and emamectin benzoate, respective- ly (0.3, 0.6, 0.9 ml/L of Spintor and 0.1, 0.2 and 0.3 g/L of Proclaim); while chromafenozide was applied at two concentrations of 37.5 and 75 mg/L (0.75 and 1.5 ml/L of Matric). The concentrations used did not exceed the manu- facturer’s recommended application rates. A non-ionic or- ganic surfactant (Agral® 600 g/L nonyl phenol ethylene oxide condensate) was added at 0.15 ml/L as a wetting agent to ensure good dispersal of the preparation. After treatments, the eggs were air-dried and held for incuba- tion. A 0.15 ml/L surfactant solution was used as a control in the experiments. Seven days following treatment the percentage of eggs hatch was recorded. The experiment consisted of three replicates for each concentration of each insecticide with a set of 1000 eggs per replicate for each age group. Larvicidal effect Experiment 1. Healthy, medium-sized potato tubers of 130-150 g weight (n≈150) were sprayed to runoff with spinosad, emamectin benzoate, and chromafenozide in- cluding surfactant at the above-mentioned concentrations, while the untreated tubers (control) were misted with sur- factant solution. All tubers were then allowed to air dry at room temperature. After treatments, tubers were depos- ited over a layer of sand in transparent plastic containers (20x12x10 cm, three tubers per container). First-instar of P. operculella larvae (<16 h old) were gently placed on the treated and untreated potato tubers (three larvae per tuber) using a fine camel-hair brush and held at the rearing con- ditions described above. The number of emerged F 1 adults was recorded. The experiment was conducted three times using a total of 1080 larvae (45x3 larvae for each concen- tration of each insecticide). Experiment 2. The experiment was carried out to deter- mine whether or not larvae hatched from insecticide-treat- ed eggs are able to survive if they are allowed to develop on untreated tubers (from a practical point of view this is only possible when insecticide-treated and untreated po- tato heaps were stored together). As described above, 1- 1.5- day-old eggs on the filter paper bands were dipped for 30 s in the respective insecticide preparations, air-dried, cut to small sections containing ten eggs and fixed on the surface of uninfested potato tubers using mini paper pins (one egg section per tuber). Eggs of the control were treated with surfactant-added water solution (0.15 ml/L). The tubers were placed in transparent plastic containers (three tubers per container) with a layer of sand completely covering the bottom of the container and held at the rear- ing conditions. The tubers were visually inspected and the number of emerged F 1 adults was noted. The experiment was repeated three times for each concentration of each insecticide with 120 eggs per replicate. Residual activity Four heaps (≈50 kg each) of healthy, medium-sized po- tato tubers were thoroughly sprayed with the respective insecticide preparations at the highest concentrations 216, 15 and 75 mg/l for spinosad, emamectin benzoate, and chromafenozide, respectively. Water/surfactant solution was used for the control treatment. After drying, the tubers were stored in the dark at room temperature (≈23°C) in order to reduce tuber weight loss and the accumulation of solanine (Haddadin et al., 2001; Gachango et al., 2008). 148 Newly hatched larvae were placed on the tubers at 0, 7, 14, 21, 28, 35, 42, 49, 60 or 90 days after insecticide ap- plications (three larvae per tuber and three tubers were placed in each plastic container). The number of emerged F 1 adults was recorded. Three replicates were retained for each stored period of each insecticide with 45 larvae per replicate. Statistical analysis Differences in egg hatchability and emergence of F 1 adults were tested by the analysis of variance (ANOVA) at the 5% level (P<0.05). Significant ANOVAs were followed by the protected least significant difference (PLSD) at α < 0.05. Differences in egg hatch between 1-1.5 and 4-4.5-day-old eggs were determined using paired-samples t-test (StatView Version 4.02; Abacus Concepts, 1994). Data were arcsine transformed prior to analysis to stabilize the variance. Dose-mortality re- sponses were estimated by probit analysis (IBM, 2010). Percentages of egg hatching and adult emergence were corrected according to Schneider-Orelli’s (Kroschel and Koch, 1996) formula: % M = (b - k/100 - k) x 100 where M = corrected %, b = % observed in the treat- ment, and k = % observed in the control. 3. Results Among the insecticides tested, ovicidal activity was observed only in spinosad preparations (Table 1). Spi- nosad at the median and high concentrations (144 and 216 mg/l) was very effective in controlling P. operculella egg hatch compared to emamectin benzoate, chromafe- nozide and control treatments. There were no significant differences in egg hatchability between emamectin ben- zoate and chromafenozide used at 5 and 37.5 mg/L and the control for 1-1.5-days-old eggs (F= 476.2; df= 8, 261; P< 0.0001). The LC 99s for 1-1.5-day-old eggs were 240.81, 97.17 and 530.32 mg/L for spinosad, emamectin benzoate and chromafenozide, respectively. 1-1.5-day- old eggs were more sensitive to emamectin benzoate and chromafenozide than 4-4.5-day-old eggs (t= 6.3; df= 29; P<0.0001 for emamectin benzoate used at 15 mg/L con- centration). A drastic reduction in the percentage of F 1 emerged adults was observed when insecticide-treated tubers were offered to P. operculella neonate larvae (Table 2). Adult emergence was completely inhibited in spinosad and em- amectin benzoate treatments compared with 72.2% in the control (F= 474.2; df= 8, 126; P<0.0001). However, 20.3 and 11.3% of F 1 adults successfully emerged in chro- mafenozide treatment at 37.5 and 75 mg/L, respectively. Significant differences were observed in the mean percentage of F 1 adults emerged from larvae that hatched from insecticide-treated eggs and fed on untreated po- tatoes compared to the control (F= 1616.5; df= 8, 99; P<0.0001) (Table 3). However, no F 1 adults emerged with spinosad treatment at 0.6 and 0.9 mg/L, while 13.4 and 18.3% of adult emergence was noted in emamectin benzoate and chromafenozide at 0.1, and 37.5 mg/L, re- spectively. The time-dependent efficacy of the tested insecticides against P. operculella is presented in Table 4. The re- sidual activity of spinosad and emamectin benzoate used at 216 and 15 mg/L remained unchanged (zero F 1 adults Table 1 - Mean (±SE) hatchability of potato tuber moth eggs of two age groups treated topically with spinosad, emamectin benzoate, and chromafe- nozide insecticides Insecticides Chemical group Active ingredient mg/l % of hatched eggs (z) 1-1.5 day old egg 4-4.5 days old egg (y) Control - 91.9±4.2Aa 94.1±3.9Aa Spinosad Spinosyns 72 12.7±3.9Ac 15.8±3.8Ac (Spintor® 2 SC, 240 mg/ml) 144 0.0±0.0Ac 6.0±1.5Bd 216 0.0±0.0Ac 1.6±0.4Ad Emamectin benzoate Avermectins 5 86.8±5.3aBb 93.7±3.3Aa (Proclaim® 05 SG, 50g/kg) 10 78.6±4.0Bab 87.4±4.5Aab 15 70.3±5.1Bb 86.3±5.1Ab Chromafenozide Non-steroidal 37,5 84.6±5.0Bab 91.6±4.1Aab (Matric® 5% SC, 50g/l) ecdysteroid agonist 75 76.9±3.9Bb 84.7±4.8Ab (z) Means in row for each egg age followed by the same uppercase letter are not significantly different (P < 0.05, t-test); means in column for each egg age followed by the same lowercase letter are not significantly different (P < 0.05, Fisher PLSD). (y) Data were corrected according to Schneider-Orelli’s formula and arcsine transformed prior to analysis; mean of three replicates, 1000 eggs per replicate for each insecticide and concentration. 149 Table 2 - Mean percentage (±SE) of potato tuber moth F 1 adults emerged from spinosad-, emamectin benzoate-, and chromafenozide-treated and untreated potato tubers Insecticides Chemical group Active ingredient mg/l F 1 emerged adults (%) (z) Control 72.2±7.84 a Spinosad (Spintor® 2 SC, 240 mg/ml) Spinosyns 72 0.0±0.0 d 144 216 Emamectin benzoate (Proclaim® 05 SG, 50 g/kg) Avermectins 5 0.0±0.0 d 10 15 Chromafenozide (Matric® 5% SC, 50 g/l) Non-steroidal 37,5 20.3±2.1 b ecdysteroid agonist 75 11.3±2.8 c (z) Means in column followed by the same letter are not significantly different (P<0.05, Fisher PLSD); data were corrected according to Schneider- Orelli’s formula and arcsine transformed prior to analysis; mean of three replicates, 45 larvae per replicate for each concentration of each insecticide. Table 3 - Mean percentage (±SE) of potato tuber moth F 1 adults emerged from spinosad-, emamectin benzoate-, and chromafenozide-treated and untreated eggs, the hatched larvae being fed on untreated tubers Insecticides Chemical group Active ingredient mg/l F 1 emerged adults (%) (z) Control 68.9±8.4a Spinosad Spinosyns 72 7.1±3.1d (Spintor® 2 SC, 240 mg/ml) 144 0.0±0.0e 216 Emamectin benzoate Avermectins 5 13.4±1.6c (Proclaim® 05 SG, 50g/kg) 10 8.1±2.0d 15 0.0±0.0e Chromafenozide Non-steroidal 37,5 18.3±4.6b (Matric® 5% SC, 50g/l) ecdysteroid agonist 75 13.1±5.1c (z) The treated eggs were at the 1-1.5 day-old egg stage; means in column followed by the same letter are not significantly different (P<0.05, Fisher PLSD); data were corrected according to Schneider-Orelli’s formula and arcsine transformed prior to analysis; mean of three replicates, 120 eggs per replicate for each concentration of each insecticide. Table 4 - Mean percentage (±SE) of potato tuber moth F 1 adults emerged from spinosad-, emamectin benzoate-, and chromafenozide-treated and untreated potato tubers several days after treatment Stored period, days after insecticides application F 1 emerged adults (%) (z) ControlSpinosad (216 mg/ml) Emamectin benzoate (15 mg/l) Chromafenozide (75 mg/l) 7 0.0 ± 0.0 c 0.0 ± 0.0 c 11.7 ± 1.5 b 70.3 ± 8.9 a 14 0.0 ± 0.0 c 0.0 ± 0.0 c 23.4 ± 4.1 b 72.1 ± 9.9 a 21 62.2 ± 6.9 a 68.9 ± 7.2 a 28 65.1 ± 6.1 a 67.9 ± 7.8 a 35 68.0 ± 9.9 a 71.0 ± 9.9 a 42 65.7 ±7.8 a 66.9 ± 6.9 a 49 68.2 ± 9.8 a 69.1 ± 9.0 a 60 70.0 ± 9.9 a 71.4 ± 9.7 a 90 0.0 ± 0.0 b 0.0 ± 0.0 b 66.3 ± 7.5 a 68.0 ± 9.6 a (z) Means in row followed by the same letter are not significantly different (P<0.05, Fisher PLSD data were corrected according to Schneider-Orelli’s formula and arcsine transformed prior to analysis; mean of three replicates, 45 larvae per replicate for each stored period of each insecticide. 150 emergence) for up to 90 days after application. In con- trast, a severe loss in efficacy occurred at the end of the two-week test period for tubers treated with chromafeno- zide. Significant differences were obtained when chro- mafenozide was compared to the other insecticides tested (F= 5714.3; df= 3, 56; P<0.0001 after 14 days of stor- age), indicating that spinosad and emamectin benzoate were more efficient in protecting potato tubers from P. operculella infestation than chromafenozide even during 14 days after application. 4. Discussion and Conclusions In general, there are few studies regarding the effect of insecticides on eggs of Lepidoptera pests and most pub- lications focus on the control of the larval stage, conse- quently, little information is available about the effect of insecticides on eggs of P. operculella. Regardless of egg developmental stages, nearly 100% mortality (or 0% egg hatch) was obtained when eggs were treated with spi- nosad at high and medium concentrations (216 and 144 mg/L, respectively), which was not the case for emamec- tin benzoate and chromafenozide. Therefore, it is obvious that spinosad has excellent embryocidal activity and the compound was able to penetrate the chorion (eggshell) and reach the developing embryos. Our results concerning the efficacy of spinosad on P. operculella egg hatchability agree with several authors who found an excellent ovicidal activity of spinosad when applied against the eggs of the Egyptian cottonworm Spodoptera littoralis (Boisd.), the cactus moth Cactoblastis cactorum (Berg), the cranberry fruitworm, Acrobasis vaccinii Riley and the diamondback moth Plutella xylostella (L.) (Bloem et al., 2005; Temer- ak, 2005; Wise et al., 2010; Mahmoudvand et al., 2011). On the other hand, El-Barkey et al. (2009) reported that a 52% reduction in percentage of egg hatching was obtained when eggs of the pink bollworm Pectinophora gossypiel- la (Saunders) were challenged with Radiant Sc 12% (the second generation of spinosad) at the LC 50 level. However, according to Perez et al. (2007), spinosad showed no ovi- cidal properties when applied against eggs of the Aedes aegypti (L.) mosquito. When P. operculella eggs were topically treated with emamectin benzoate and chromafenozide either at low and medium, or at high concentrations, egg hatchability was not prevented. However, at the highest concentrations, a weak ovicidal effect was noted and eggs hatching were significantly reduced by 8.3 and 10% at the concentrations of 15 and 75 mg/L for emamectin benzoate and chromafe- nozide, respectively. Our data corroborate the results that emamectin benzoate used in field experiments at the rate of 13.5 g AI/ha had no ovicidal effect on the minute pirate bug Orius albidipennis (Reuter) (Sechser et al., 2003). In fact, emamectin benzoate was registered as lepidopteran larvicidal insecticide, which means that the product must be ingested by Lepidoptera larvae to be effective. Accord- ingly, Scarpellini (2001) reported that all larval stages of the cotton leafworm Alabama argillacea Hübner died 12 h after they started eating cotton leaves treated with ema- mectin at 9.6 g AI/ha. Not surprisingly, we found no effect of chromafenozide on the mean percentage of egg hatch. Chromafenozide, like other inhibitors of ecdysteroid biosynthesis, shows toxic effects against larvae of lepidopteran pests mainly via digestion (Yanagi et al., 2006). In this respect, Slama (1995) reported that the ecdysone agonists were complete- ly ineffective in all methods of topical application against the ligated larvae of Galleria mellonella L., Manduca sexta (L.) and Pieris brassicae (L.). Nonetheless, Kandil et al. (2012) reported that the hatchability of 1-d-old eggs of P. gossypiella was 53% when they were treated with chromafenozide at the LC 50 level compared with 97.0% in the control. Our data show that the older eggs (4-4.5 days old) were relatively more tolerant to insecticides than the younger ones (1-1.5 days old). In general, the hatchability of Lepi- doptera eggs following insecticide treatments depends on the compound, dose, and age of eggs (Gelbic et al., 2011). The relative sensitivity of newly laid eggs to insecticides compared to those of older age classes can be attributed, at least in part, to chorion hardening during the embryo de- velopment that obstructs the penetration of external prod- ucts (Tavares et al., 2011). P. operculella neonate larvae exhibited a high response (100% mortality) to all concentrations tested of spinosad and emamectin benzoate, however low numbers of larvae that challenged chromafenozide-treated tubers achieved their development and emerged as F 1 adults (the percent- age of emerged adults was relatively high when the com- pound was used at the low concentration). These findings agree with the data reported by other researchers regarding the larvicidal efficacy of spinosad, emamectin benzoate and chromafenozide in controlling several lepidopteran pests (Kandil et al., 2012; Abouelghar et al., 2013; Dong et al., 2013; Nasir et al., 2013; Tong et al., 2013). When P. operculella larvae hatched from spinosad-, emamectin benzoate-, and chromafenozide-treated eggs were fed on untreated tubers, the percentages of F 1 emerged adults were completely inhibited for spinosad and emamectin benzoate used at medium and high con- centrations and drastically reduced for chromafenozide treatment. It seems probable that treated-egg chorion re- tained toxic residues to cause the death of newly hatched L1 larvae which puncture the eggshell and eat their way through while hatching. It’s worth mentioning that when we evaluated the results concerning the emamectin ben- zoate and chromafenozide treatments, we found that P. operculella neonate larvae had been successful at creat- ing a small opening in the eggshell during the process of exiting the chorion; however, most of the larvae failed to survive and died without feeding in close proximity to the egg. This indicates that although these two compounds do not have ovicidal activity, they have demonstrated ovi- larvicidal activity when applied topically after eggs have been laid. Our data concerning the ovi-larvicidal activity 151 of emamectin benzoate and chromafenozide are congruent with studies on the effects of these insecticides and other insecticides with ecdysone mode of action on Helicoverpa armigera Hübner and A. vaccinii (Dhadialla et al., 2005; Wise et al., 2010; Singh and Kumar, 2012). Determination of residual activity of an insecticide is essential information to protect agricultural products from re-infestation. Spinosad and emamectin benzoate pro- vide, under protected environments (complete darkness), a 100% residual control effect up to 90 days after appli- cation, while chromafenozide applied at 75 mg/L showed limited residual activity of 7 to 14 days. Therefore, P. operculella larvae exposed to chromafenozide-treated tu- bers at 21 days following treatment continued their devel- opment and reached the adult stage. The extended period of residual activity of spinosad and emamectin benzoate could be related to the rate of their photodegradation, since these two compounds are known to undergo relatively rapid photodegradation via photolysis (primary route of degradation) that ultimately affects their residual toxicity (Liu et al., 1999; Jones et al., 2005; Zhu et al., 2011). Our insecticide-treated potatoes were stored in total darkness and this could explain the slow degradation of spinosad and emamectin benzoate under our experimental laborato- ry conditions. On the other hand, Ditya et al. (2012) found that the dissipation rate (half-life) of chromafenozide ap- plied to different types of soil samples in laboratory condi- tions was between 15.8 and 23.9 days. In conclusion, the results of this study are the first pub- lished data on the efficacy of spinosad, emamectin ben- zoate and to a lesser extent chromafenozide against P. operculella eggs and neonate larvae and demonstrate that these compounds could be used as replacements for earli- er insecticide classes. Moreover, spinosad and emamectin benzoate proved to be highly effective in protecting pota- toes from P. operculella infestation almost completely for three months and therefore they could be successfully used in unrefrigerated rustic potato stores. Acknowledgements Thanks are due to Dr. I. Othman (General Director) and Dr. N. Mirali for their help and support. References ABACUS CONCEPT, 1994 - StatView, Version 4.02 - Abacus Concepts, Berkeley, CA. ABOUELGHAR G.E, SAKR H., AMMAR H.A., YOUSEF A., NASSAR M., 2013 - Sublethal effects of spinosad (Tracer®) on the cotton leafworm (Lepidoptera: Noctuidae). - Journal of Plant Protection Research, 53: 275-284. AYDIN H., GüRKAN M.O., 2005 - The efficacy of Spinosad on different strains of Spodoptera littoralis (Boisduval) (Lepi- doptera: Noctuidae). - Turkish Journal of Biology, 30: 5-9. BLOEM S., MIZELL R.F., BLOEM K.A., HIGHT S.D., CAR- PENTER J.E., 2005 - Laboratory evaluation of insecticides for control of the invasive Cactoblastis cactorum (Lepidop- tera: Pyralidae). - Florida Entomologist, 88: 395-400. CAMERON P.J., WALKER G.P., PENNY G.M., WIGLEY P.J., 2002 - Movement of potato tuberworm (Lepidoptera: Gel- echiidae) within and between crops, and some comparisons with diamondback moth (Lepidoptera: Plutellidae). - Envi- ronmental Entomology, 31: 65-75. CLOUGH G.H., RONDON S.I., DEBANO S.J., DAVID N., HAMM P.B., 2010 - Reducing tuber damage by potato tu- berworm (Lepidoptera: Gelechiidae) with cultural practices and insecticides. - Journal of Economic Entomology, 103: 1306-1311. DHADIALLA T.S., RETNAKARAN A., SMAGGHE G., 2005 - Insect growth- and development-disrupting insecticides, pp. 121-184 - In: LAWRENCE I.G., KOSTAS I., SARJEET S.G. (eds.) Comprehensive Insect Molecular Science, vol- ume 6: Control. Pergamon, Elsevier, Oxford, UK. DILLARD H.R., WICKS T.J., PHILIP B., 1993 - A grower survey of diseases, invertebrate pests, and pesticide use on potatoes grown in South Australia. - Australian Journal of Experimental Agriculture, 33: 653-661. DITYA P., DAS S.P., BHATTACHARYYA A., 2012 - Degrada- tion dynamics of chromafenozide in different types of soil. - Bulletin of Environmental Contamination and Toxicology, 89: 322-327. DONG W., YONG-MING W., HUI-YUAN L., ZHENG X., MING X., 2013 - Lethal and sublethal effects of spinosad on Spodoptera exigua (Lepidoptera: Noctuidae). - Journal of Economic Entomology, 4: 1825-1831. EDOMWANDE E.O., SCHOEMAN A.S., BRITS J.A., VAN DER MERWE M., 2000 - Laboratory evaluation of lufenu- ron on immature stages of potato tuber moth (Lepidoptera: Gelechiidae). - Journal of Economic Entomology, 93: 1741- 1743. EL-BARKEY N.M., AMER A.E., KANDEEL M.A., 2009 - Ovicidal activity and biological effects of Radiant and Hexa- flumuron against eggs of pink bollworm, Pectinophora gos- sypiella (Saunders) (Lepidoptera: Gelechiidae). - Egyptian Academic Journal of Biological Sciences, 2: 23-36. EUROPEAN FOOD SAFETY AUTHORITY, 2013 - Conclu- sion on the peer review of the pesticide risk assessment of the active substance chromafenozide. - EFSA Journal, 11(12): 3461. GACHANGO E., SHIBAIRO S.H., KABIRA J.N., CHEMINING’WA G.N., DEMO P., 2008 - Effects of light intensity on quality of potato seed tubers. - African Journal of Agricultural Research, 3: 732-739. GELBIC I., ADEL M.M., HUSSEIN H.M., 2011 - Effects of nonsteroidal ecdysone agonist RH-5992 and chitin biosyn- thesis inhibitor lufenuron on Spodoptera littoralis (Boisdu- val, 1833). - Central European Journal of Biology, 6: 861- 869. HADDADIN M.S.Y., HUMEID M.A., QAROOT F.A., ROB- INSON R.K., 2001 - Effect of exposure to light on the sola- nine content of two varieties of potato (Solanum tuberosum) popular in Jordan. - Food Chemistry, 73: 205-208. IBM, 2010 - IBM SPSS Statistics 19. - IBM Software, Chicago, IL, USA. IORIATTI C., ANFORA G., ANGELI G., CIVOLANI S., 152 SCHMIDT S., PASQUALINI E., 2009 - Toxicity of ema- mectin benzoate to Cydia pomonella (L.) and Cydia molesta (Busck) (Lepidoptera: Tortricidae): laboratory and field tests. - Pest Management Science, 65: 306-312. ISHAAYA I., KONTSEDALOV S., HOROWITZ A.R., 2002 - Emamectin, a novel insecticide for controlling field crop pests. - Pest Management Science, 58: 1091-1095. JONES T., SCOTT-DUPREE C., HARRIS R., SHIPP L., HAR- RIS B., 2005 - The efficacy of spinosad against the western flower thrips, Frankliniella occidentalis, and its impact on associated biological control agents on greenhouse cucum- bers in southern Ontario. - Pest Management Science, 61: 179-185. KANDIL M.A., AHMED A.F., MOUSTAFA H.Z., 2012 - Toxi- cological and biochemical studies of lufenuron, chlorflua- zuron and chromafenozide against Pectinophora gossypiella (Saunders). - Egyptian Academic Journal of Biological Sci- ences, 4: 37- 47. KROSCHEL J., KOCH W., 1996 - Studies on the use of chemi- cals, botanicals, and Bacillus thuringiensis in the manage- ment of the potato tuber moth in potato stores. - Crop Protec- tion, 2: 197-203. LEGOCKI J., POLEC I., ZELECHOWSKI K., 2010 - Contem- porary trends in development of active substances possess- ing the pesticidal properties: spinosyn insecticides. - Pesti- cides, 1: 59-71. LIU T.X., SPARKS A.N., WILLIAM J.R., HENDRIX W.H., YUE B., 1999 - Effects of Spintor (spinosad) on cabbage looper (Lepidoptera: Noctuidae): toxicity and persistence of leaf residue on cabbage under field and laboratory condi- tions. - Journal of Economic Entomology, 92: 1266-1273. MAHMOUDVAND M., GARJAN A.S., ABBASIPOUR H., 2011 - Ovicidal effect of some insecticides on the diamond- back moth, Plutella xylostella (L.) (Lepidoptera: Yponomeu- tidae). - Chilean Journal of Agricultural Research, 71: 226- 230. NAKAGAWA Y., 2005 - Nonsteroidal ecdysone agonists. - Vita- mins and Hormones, 73: 131-73. NASIR M., IMRAN M., AHMAD M., 2013 - Pyrethroids syner- gize new chemical insecticides in field populations of Plutel- la xylostella (Lepidoptera: Plutellidae). - Pakistan Journal of Zoology, 45: 629-633. PEREZ C.M., MARINA C.F., BOND J.G., ROJAS J.C., VALLE J., WILLIAMS T., 2007 - Spionosad, a naturally derived in- secticide, for control of Aedes aegypti (Diptera: Culicidae): Efficacy, persistence, and elicited ovipostion response. - Journal of Medical Entomology, 44: 631-638. SALGADO V.L., 1998 - Studies on the mode of action of spi- nosad: insect symptoms and physiological correlates. - Pes- ticide Biochemistry and Physiology, 60: 91-102. SAOUR G., 2008 - Effect of thiacloprid against the potato tuber moth Phthorimaea operculella Zeller (Lepidoptera: Gelechi- idae). - Journal of Pest Science, 81: 3-8. SCARPELLINI J.R., 2001 - Effect of emamectin benzoate on several larval stages of cotton leafworm Alabama argillacea Hüb. (Lepidoptera: Noctuidae). - Arquivos do Instituto Bi- ológico (São Paulo), 68: 57-61. SECHSER B., AYOUB S., MONUIR N., 2003 - Selectivity of emamectin benzoate to predators of sucking pests on cotton. - Journal of Plant Diseases and Protection, 110: 184-194. SINGH A.K., KUMAR A., 2012 - Evaluation of new molecules in IPM modules against Helicoverpa armigera (Hübner) in chick pea. - Annals of Plant Protection Sciences, 20: 19-23. SLAMA K., 1995 - Hormonal status of RH-5849 and RH-5992 synthetic ecdysone agonists (ecdysoids) examined on several standard bioassays for ecdysteroids. - European Journal of Entomology, 92: 317-323. SYMINGTON C.A., 2003 - Lethal and sublethal effects of pes- ticides on the potato tuber moth, Phthorimaea operculella (Zeller) (Lepidoptera: Gelechhidae) and its parasitoid Orgi- lus Lepidus Muesebeck (Hymenoptera: Braconidae). - Crop Protection, 22: 513-519. TAVARES W.S., CRUZ I., PETACCI F., FREITAS S.S., SER- RãO J.E., ZANUNCIO J.C., 2011 - Insecticide activity of piperine: Toxicity to eggs of Spodoptera frugiperda (Lepi- doptera: Noctuidae) and Diatraea saccharalis (Lepidoptera: Pyralidae) and phytotoxicity on several vegetables. - Journal of Medicinal Plants Research, 5: 5301-5306. TEMERAK S.A., 2005 - Ovicidal activity of the natural bio-prod- uct spinosad through field observation of tagged egg masses of Spodoptera littoralis on cotton, in five governorates of Egypt. - Assiut. Journal of Agricultural Science, 36: 85-92. THOMPSON G.D., DUTTON R., SPARKS T.C., 2000 - Spi- nosad - a case study: an example from a natural products discovery programme. - Pest Management Science, 56: 696- 702. TONG H., SU Q., ZHOU X., BAI L., 2013 - Field resistance of Spodoptera litura (Lepidoptera: Noctuidae) to organophos- phates, pyrethroids, carbamates and four newer chemistry insecticides in Hunan, China. - Journal of Pest Science, 86: 599-609. WANG D., WANG Y.M., LIU H.Y., XIN Z., XUE M., 2013 - Le- thal and sublethal effects of spinosad on Spodoptera exigua (Lepidoptera: Noctuidae). - Journal of Economic Entomol- ogy, 106: 1825-1831. WISE J.C., JENKINS P.E., VANDER POPPEN R., ISAACS R., 2010 - Activity of broad-spectrum and reduced-risk insec- ticides on various life stages of cranberry fruitworm (Lepi- doptera: Pyralidae) in highbush blueberry. - Journal of Eco- nomic Entomology, 103: 1720-1728. YANAGI M., TSUKAMOTO Y., WATNABE T., KAWAGISHI A., 2006 - Development of a novel lepidopteran insect con- trol agent, chromafenozide. - Journal of Pesticide Science, 31: 163-164. ZHU J., HE Y., GAO M., ZHOU W., HUA J., SHEN J., ZHU Y.C., 2011 - Photodegradation of emamectin benzoate and its influence on efficacy against the rice stem borer, Chilo suppressalis. - Crop Protection, 30: 1356-1362.