Evaluate the Effects of Potential Botanical and Conventional Insecticides on the Reproductive and Developmental Aspects of the Pest Agrotis Ipsilion (Lepidoptera: Noctuidae)

Abstract

Background: Agrotis ipsilon (Hüfn.), is known as a hazardous destructive pest for corn, Zea mays (L.) in Egypt, where it negatively affects corn yield production. Using insecticides continuously were sharply affected the progress of pest development in the field. The frequent uses of chemical pesticides to protect field crops leads to the development of insecticide-resistant strains. Aim: Evaluate the insecticidal effect of four plant extracts with insecticidal properties and a chemical insecticide to control A. ipsilon using biological parameters and fertility life table. Also, to estimate the effects of these insecticidal materials on population growth, developmental progress, and nutritional indices and hence make recommendation of the type of insecticides to be used in Integrated Pest Management Programs. Methodology: 1- Tested materials: (1) chemical insecticide (Chlorfenapyr at 0.5% concentration). (2) Four plant extracts (petroleum ether extracts of both Melia azedarach and Vinca rosea, and alcohol & hexane extracts of Conyza aegyptiaca) at 5% concentration each. 2- Tested insect: Agrotis ipsilon (the egg stage and the 4th larval instar). 3- Bioassay: Eggs and larvae were treated with tested materials separately, then different biological parameters were calculated. 4- Life table parameters: Life table parameters were calculate using  the “Age-stage, two-sex life tables” computer program. Results: The obtained data revealed that petroleum ether extracts of V. rosea and M. azedarach were the best antifeedant agents against the 4th larval instar of A. ipsilon. The female longevity was significantly shortened under the effect of both treatments of M. azedarach and Challenger insecticide. All tested materials reflected an effective decline in the female ability for laying eggs, where this effect was obvious in the case of M. azedarach and Challenger insecticide treatments. It was found that the Melia treatment prolonged the incubation and developmental periods for the immature stages leading to a reduction of some life table parameters of A. ipsilon and also increase the generation mean time. Conclusion: The resultant data obtained in this work may help in the usage of plant extracts in the advancement of IPM programs for the greasy cutworm, (Agrotis ipsilon) in Egypt.