ABSTRACT
An analysis of the 11 years of population estimates for the cereal aphids, Sitobion avenae and Metopolophium dirhodum, on wheat in south-eastern England, plus shorter runs of data for other areas, has revealed easily measurable factors that are correlated with flight activity and peak population size. These can be used to give a relatively long-term forecast of the likelihood of outbreaks and a more accurate short-term forecast of the peak numbers. Further improvement is largely dependent on even longer runs of field data and on the integration of data collected in different regions.
