Published online by Cambridge University Press: 10 July 2009
The efficiencies of people sampling cabbage plants in the field for total numbers of Myzus persicae (Sulzer) were found to differ. Significantly more aphids were counted on leaves taken to the laboratory than on leaves examined by inexperienced people in the field, but field counts by an experienced person did not differ significantly from the laboratory sample. The implications of differences between people and the possibility of correcting for them in surveys are discussed.