SUSCEPTIBILITY OF THE ONION MAGGOT, DELIA ANTIQUA (DIPTERA: ANTHOMYIIDAE), TO THE MYCOTOXIN DESTRUXIN E

Abstract

The onion maggot, Delia antiqua (Meigen), is the most important pest of Allium spp. in temperate regions of the northern hemisphere (Loosjes 1976; Ellis and Eckenrode 1977). If left uncontrolled, the onion maggot can cause from 20 to 100% crop losses, especially in light organic soils. In the early 1950's, with the development of organochlorine insecticides, onion growers obtained good control of onion maggot populations (Finlayson et al. 1959), but the pest rapidly developed resistance to these toxicants (Harris 1977). The chlorinated hydrocarbons were replaced by the less persistent organophosphorus and carbarnate insecticides (Hanis et al. 1981), but the onion maggot was reported to become resistant to these compounds (Harris et al. 1981; Carroll et al. 1983). Among alternatives to the use of insecticides to control the onion maggot are the entomopathogenic fungi and their metabolites. The potential of mycotoxins as rnicrobially derived insecticides has been investigated by several researchers and reviewed recently by Roberts (1981).