The effects of foliar fungicides on beneficial arthropods in wheat fields.

Abstract

Large scale replicated field trials were carried out over a 2 year period to quantify the insecticidal properties of 3 foliar fungicides commonly used in wheat fields. Pyrazophos significantly reduced the numbers of many groups of the natural enemies of cereal aphids and the insects known to be vital in the diet of gamebird chicks for up to 4 weeks after spraying. No such reductions were found after the use of either triadimefon or propiconazole.

Aphid numbers on plots sprayed with pyrazophos were twice the numbers found on unsprayed plots either 6 weeks after spraying in 1985 or on unsprayed plots and plots sprayed with the other fungicides 20 days after treatment in 1984. In 1985, this necessitated the additional use of an aphicide only on those plots previously sprayed with pyrazophos. The removal of chick food insects following the use of pyrazophos was considered to be sufficient to reduce survival rates of wild gamebird chicks.