Effects of european corn borer control on aphids and theirs natural enemies in maize stands

Abstract

Over the period of July to September 2005 effects of insecticide Integro with the effective substance methoxifenozide and biological preparation Trichoplus using parasitoid wasps Trichogramma evanescens and T. pintoi were evaluated in maize stands. These natural enemies of aphids were recorded in monitored fields (located in South Moravia, Czech Republic): parasitoids of genera Aphidius and Praon (Hymenopetra, Aphidiidae), predatory syrphid flies (Diptera, Syrphidae), ladybirds (Coleoptera, Coccinellidae), Orius bugs (Heteroptera, Anthocoridae), Green Lacewing - Chrysoperla carnea (Neuroptera, Chrysopidae) and spiders (Araneida). No significant difference (T = 0.003; F = 4.894; P = 0.004) in populations of aphids and their antagonists was found in the studied variants (Integro, Trichoplus). More remarkable differences were found only soon after spraying with Integro. Syrphid flies pupae decreased by 41% in the Integro variant, and by 13% in the Trichoplus variant. Ladybird larvae did not occur in the Integro variant after spraying, there where 0.12 ladybird larvae on plant in the Trichoplus variant. Number of ladybird adults increased from 0.01 to 0.53 individuals per plant in the Trichoplus variant, but from 0.03 to 0.1 individuals in the Integro variant. Number of ladybird pupae decreased from 0.32 to 0.02 pupae per plant in the Integro variant, but it has increased from 0.04 to 0.54 in the Trichoplus variant. Correlative relationship between ladybird adult growing coefficient and aphid populations in the Trichoplus variant was found.