اثرات کشنده و غیرکشنده‌ی دو حشره‌کش تنظیم کننده‌ی رشد حشرات روی کرم قوزه‌ی پنبه، Helicoverpa armigera (Hub.) (Noctuidae: Lepidoptera)

The insect growth regulators (IGRs) are one of the most promising chemical compounds by devastating properties against endocrine system which affect development, reproduction and metamorphosis of insects from several orders. Although benzoylureas prevent chitin synthesis in many insects but it has no or only mild effects on fungi, parasitoids, and other natural enemies of insects. Thus these insecticides may be considered as the potential candidates with the important roles in a successful IPM program. American bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), is one of the most important pests of agricultural crops around the world which causes the high economic damages. In this study the effects of hexaflumuron and lufenuron were evaluated on third instar larvae of H. armigera. Effects of the insecticides were assessed by incorporating different concentrations of the given compounds prepared with Tween®–80 solution (0.05%) into the artificial diet. Based on the preliminary experiments, five concentrations of each compound were prepared. Dose - response bioassay tests were done and lethal concentrations were calculated. LC50 values for hexaflumuron and lufenuron were 6.16 and 61.31 mg ai/l, respectively. Sublethal effects of hexaflumuron and lufenuron were assessed using LC10 concentration of the insecticides. The results of the sublethal effects study showed that the application of LC10 value of insecticides cause significant changes in several biological parameters. Mean larval and pupal weight significantly decreased after treatment with LC10 of the insecticides. larval and pupal development durations were increased, significantly. Also, male and female longevity, egg oviposition number and egg hatch were significantly reduced after treatment. In conclusion, both insecticides will likely negatively alter the population dynamics of H. armigera, and have high potential in integrated pest management of this insect.