Abstract:

        Athelis lepigone(Möschler) is a new pest doing serious damage to summer corn. Selecting effective insecticides can guide its field prevention and control. We employed dipping method to determine the contact toxicity of 12 kinds of insecticides to fieldcollected 5th and the laboratory bred 4th instar larvae. Results indicate that 40% phoxim EC, 480 g·L^-1chlorpyrifos EC and 4.5% beta cypermethrin EW have better poisonous effects on 4th and 5th instar larvae. The LC50 of 40% phoxim EC, 480 g·L^-1chlorpyrifos EC and 4.5% beta cypermethrin EW to 4th instar larvae of A. lepigone are 0.244 mg·L^-1, 0.308 mg·L^-1 and 0.406 mg·L^-1 after 72 hours. Their relative toxicity indexes are 5.9, 4.7 and 3.6 times that of 30% acephate EC. Poisonous activity of insecticides to A. lepigone depends on insecticide type, formulation type, local insecticide employment history and the instar of larva. Phoxim EC, chlorpyrifos EC and beta cypermethrin EW should be preferentially selected to perform spraying, root pouring or insecticide mixed earth in the period of lowage instars of A. lepigone.

Key words: Athelis lepigone(Möschler), insecticide, activity