The reproductive capacity of S. exigua is significantly reduced in Delta-SEL and Gos-SEL populations compared with the control group (SS-Strain). Elevation of the major detoxification enzyme cytochrome P450 monooxygenase and esterase might have an important role in inducing tolerance to deltamethrin in gossypol-fed S. exigua populations. This study enhances our understanding of detoxification enzyme pathways for S. exigua gene expression and their role in responses to insecticides and plant secondary metabolites. © 2018 Society of Chemical Industry.

Life table and predation data were collected for Coccinella septempunctata (Linnaeus) (Coleoptera: Coccinellidae) feeding on three different host aphid species, Aphis craccivora (Koch) (Hemiptera: Aphididae), Lipaphis erysimi (Kaltenbach) (Hemiptera: Aphididae), and Myzus persicae (Sulzer) (Hemiptera: Aphididae), under laboratory conditions, using age-stage, two-sex life table. The preadult developmental period of C. septempunctata was the shortest on M. persicae (21.12 d) and the longest on A. craccivora (28.81 d). Net reproductive rate (R0) ranged from 77.31 offspring per individual on A. craccivora to 165.97 offspring per individual on M. persicae. Mean generation time (T) ranged from 39.10 d on M. persicae to 51.96 d on L. erysimi. Values of the intrinsic rate of increase (r) decreased in the order M. persicae, A. craccivora, and L. erysimi (0.1302, 0.0864 and 0.0848 d-1, respectively). The highest finite rate of increase (λ) was observed on M. persicae (1.1391 d-1) and the lowest was observed on A. craccivora and L. erysimi (1.0903 and 1.0885 d-1, respectively). This information will be useful in relation to the mass rearing of C. septempunctata in biological control systems.

Spotted bollworm, Earias vittella, is one of the most serious and devastating insect pests of vegetables and cotton. Currently insecticides are necessary for its control in nearly all crop systems. In this paper we evalute the sub-lethal effects of lufenuron on biological traits and activity of detoxification enzymes; cytochrome P450 monooxygenases, esterase and glutathione S-transeferase (GST) in second instar larvae of E. vittella. Results showed that sub-lethal concentrations (LC15 and LC40 of lufenuron, prolonged larval period (at LC40 = 13.86±1.22 d, LC15 = 13.14±1.15 d, control = 12.28±0.7), pupal duration (LC40 = 11.1± d, LC15 = 11.8±0.28 d, control = 9.40±0.52) and extended mean generation time (LC40 = 27.3±0.43 LC15 = 29.0±1.19 d, control = 26.0±0.65). Sub-lethal exposure significantly prolonged the pre-adult stage, decreased pupal weight and reduced adult longevity in the parent (F0) and F1 generation. Moreover, the fecundity and egg viability were significantly lowered in parental and F1 generations at both sublethal concentrations compared to the control. While no significant effects were noted on reproductive parameters such as the intrinsic rate of increase (r), finite rate of increase (λ), and net reproduction rate (R0) of F1 generation when compared to the control. Only mean generation time (T) in F1 at LC15 was significantly longer compared to the LC40 and control (LC40= 3.79±0.37, LC15 = 32.28±1.55d, control= 29.79±0.55). Comparatively, the activities of cytochrome P450 monooxygenases and esterase were higher than GST in treated populations.The increase in resistance development against insecticides may possibly because of elevated activity of detoxification enzymes. These results provide useful information for monitoring resistance in integrated pest management (IPM) programs for E. vittella.

Insecticide resistance is a major challenge in successful insect pest control as the insects have the ability to develop resistance to various widely used insecticides. Butene-fipronil is a novel compound with high toxicity to insects and less toxicity to the non-target organisms. In the present study, the effect of butene-fipronil alone and in combination with three enzyme inhibitors, piperonyl butoxide (PBO), diethyl maleate (DEM), and triphenyl phosphate (TPP), was carried out on larvae and adults of Drosophilia melanogaster. Our results indicated that the co-toxicity indices of butene-fipronil + PBO, butene-fipronil + TPP, and butene-fipronil + DEM mixtures were 437.3, 335.0, and 210.3, respectively, in the second-instar larvae, while 186.6, 256.2, and 238.5, respectively, in the adults, indicating synergistic effects. Interestingly, butene-fipronil increased the expression of CYP28A5 in the larvae; CYP9F2, CYP304A1, CYP28A5, and CYP318A1 in the female adults; and CYP303A1 and CYP28A5 in the male adults. Furthermore, high-level expression of Est-7 was observed in the female adults compared to larvae and male adults. Our results suggest that there is no difference in butene-fipronil metabolism in larvae and male and female adults of D. melanogaster.

Cotton is a major cash crop and backbone of the textile industry in Pakistan which is badly affected by sucking insects. Drought is an important abiotic factor in trichome development. The objective of the study was to determine the effects of drought on trichome density and length. Trichome density was measured in two ways, one through the scaling method and the other through counting the trichome density manually. The scaling method is qualitative grading while quantitative grading includes trichomecount in a card of optimized length. Three scales were finalized to classify leaves on the basis of trichomes which were counted in a specific area (0.25cm2) on abaxial side of the leaf. In drought stress, trichomes density and length were measured and compared to that in normal conditions. Trichome density varies from 12 to 56 in 0.25cm2 under drought stress. On the basis of correlation of trichome density with stomatal conductance, photosynthetic rate, PAR and transpiration ratio under drought and normal conditions, it was concluded that trichome density increased as a result of drought stress.