Evaluation of pesticides for use with biological control

Abstract

Integrated pest control programmes frequently involve both biological control with predators and parasites, and pesticide applications. It is, therefore, essential to evaluate the hazard that pesticide applications present to these insects; and this can only be done realistically under field conditions which take into account the many relevant factors such as life cycle and habits of each species, their susceptibility to the pesticide formulation, the timing and method of application, and the state of the crop. Field trials, whether in glasshouse, orchard or arable crops, may be short-term experiments, estimating populations of pests, predators and parasites before and after treatment; or long-term observations of effects of pesticide usage on populations. However, experimentation in the laboratory, under controlled environment conditions and in small plots, are essential in order to understand the interactions observed or anticipated in the field. Estimations of acute toxicity measure relative susceptibility to alternative pesticides, selectivity between pest and beneficial species, and relative activity to different stages in the life cycle. Other tests determine the effects of sublethal doses, particularly on the ability of species to continue to parasitise and predate (i.e. ‘beneficial capacity’), and of different methods of pesticide application. The significance of the many techniques which have been described, their suitability for obtaining the required information, and the interpretation of results, are discussed.