Forecasting outbreaks of the grain aphid.

Abstract

Outbreaks of grain aphid, Sitobion avenae, occur sporadically depending on interactions between (i) the timing and number of alate immigrants entering a crop, (i i) weather during and after immigration and (i i i) the abundance of natural enemies. The effects of adverse weather such as heavy rain on aphid population development have not been quantified but more information is available on natural enemies and aphid immigration. This paper describes an  attempt to simulate and quantify interactions between aphids and their natural enemies with  the long-term aim of predicting in which years the latter are likely to prevent aphid outbreaks .