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Asiatic rice borer, Chilo suppressalis (Walker) (Lepidoptera: Crambidae), is a cosmopolitan and destructive pest in rice fields of the world. This pest was reported in 1973 in Iran, and it has since spread widely in rice, Oryza sativa L., fields throughout the country. In this study, we tried to evaluate comparative toxicity of diazinon in five colonies of C. suppressalis, collected from Babol (Ba), Amol (Am) of Mazandaran Province and Rasht (Ra), Sheikhmahale (Sh), and Gourabzarmikh (Go) of Guilan Province, northern Iran. The LD50 values were compared. We also evaluated the general esterases, alkaline phosphatase (ALP), glutathione transferase (GST), and acetylcholinesterase (AChE) activities from the five populations. The LD50 values of Ra, Ba, Am, and Sh (12.64, 11.4, 7.17, and 3.71 microg/mg larva(-1)) were 13.67-, 12.33-, 7.75-, and 4.02-fold higher than Go population (0.924 microg/mg larva(-1)). Using alpha-naphthyl acetate as substrate, the general esterase activities in Ra, Ba, Am, and Sh colonies were, respectively, 1.81-, 1.68-, 1.75-, and 1.35-fold more than those in Go population. When beta-naphthyl acetate was used as the substrate, activity ratio was measured 1.98-, 2.58-, 1.25-, and 1.24-fold compared with the Go population. Glutathione transferase activities in Ra, Ba, Am, and Sh populations were 1.27-, 1.68-, 0.98-, and 1.7-fold more than those in Go, when 1-chloro-2,4-dinitrobenzene was used as the substrate. When 1,2-dichloro-4-nitro-benzene was used as the substrate, activity ratio was measured 1.14-, 1.42-, 0.56-, and 0.95-fold compared with Go population. The ALP activity demonstrated a significant difference among these populations and in Ra, Ba, Am, and Sh larvae were 3.54-, 4.62-, 3.84-, and 2.18-fold more than Go. The AChE inhibition or I50 value was 0.19, 0.22, 0.31, 0.19, and 0.26 mM in Ra, Ba, Am, Sh and Go populations, respectively. However, the results showed no significant differences in studied colonies. These biochemical characterizations of general esterases ALP, GST, and AChE were consistent with diazinon bioassay in the five populations. It is inferred from increased esterase, alkaline phosphatase and glutathione transferase, activities that might play an important role in the increasing resistance in C. suppressalis to diazinon among these five populations.

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Insect growth regulators generally have a selective effect on the target insects and have practically no apparent side effect on non-target organisms especially vertebrates. Hence, insect growth regulators could be a suitable choice to control pests in stored products. Ten-day-old larvae of Indian meal moth Plodia interpunctella (Hübner) were expressed to the juvenile hormone analogue pyriproxyfen in order to have an effect on growth, metamorphosis, reproduction, lipid and protein contents of ovaries. The larvae were treated by 0.02, 0.04, 0.08, 0.16, and 0.3 ppm of JHA in an artificial diet where controls received acetone alone. The results indicated significant differences in duration of growth, mean longevity of hatched adults, percentage of emerged normal adults, abnormal pupae, hatched larvae and mean oviposition ratein addition to the lipid and protein of ovaries compared to the controls. An inhibition concentration of fifty (IF 50 ) for prevention of emerging adults was recorded 0.134 ppm. Pyriproxyfen caused significant defects in the legs and wings of some adults and sever morphological changes in the ovaries of emerged adults. The results showed that pyriproxyfen may be applied as an insecticide to decrease the damage caused by Indian meal moth on stored products. Pyriproxyfen can be used with low side effects to humans.

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Methanolic extract of Artemisia annua L. were evaluated on growth and nutritional efficiency of lesser mulberry pyralid Glyphodes pyloalis (Lepidoptera: Pyralidae) in laboratory conditions (24±1°C, 75±5% RH and 16 L : 8 D). Feeding deterrence index was evaluated by a choice test method on < 24 h fifth instar larvae with 5, 2.5, 1.25 and 0.625 percent of the extract. The result indicated that increasing the concentration resulted in higher deterrence. The extract retarded larval growth significantly (EC 50 = 3.63%) and also showed significant effects on the relative growth rate (RGR), efficiency of conversion of ingested food (ECI), efficiency of conversion of digested food (ECD), approximate digestibility (AD) and consumption index (CI). Lipid, protein and carbohydrate in treated insects were significantly reduced compared to the controls. Hence, methanol extract of A. annua could be considered as a strong deterrent which also affects the biochemical metabolism of the target pest. Methanol extract of A. annua has the potential for development as a botanical insecticide.

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