Assessment of methods for estimating the numbers of aphids (Hemiptera: Aphididae) in Cereals

Abstract

Visual counting was found to be the most accurate method of estimating cereal aphid numbers in field studies in England. Vacuum sampling decreased in efficiency as aphid density increased, but could be a useful alternative to visual counts at very low aphid densities when the latter became too time-consuming. Cutting tillers for later washing in the laboratory was less efficient than visual counting as aphids, especially Metopolophium dirhodum (Wlk.), fell off the plants during sampling, but this method was useful in determining the proportion of different morphs of Sitobion avenae (F.) present at very high densities.