The biology and pest status of cereal aphids (Hemiptera: Aphididae) in Europe: a review.

Abstract

The biology and pest status of the common species of Sitobion, Metopolophium and Rhopalosiphum found on wheat, barley and oat crops in Europe is critically reviewed. After preliminary sections on species and sampling, the factors that induce the production of the different morphs of cereal aphids are considered. Basic life-cycles are described and the importance of migration and dispersal considered. Host-plant preferences, survival and reproduction on different Gramineae, and feeding site preferences are considered, particularly in relation to the type and amount of damage caused by the aphids. The effects of constant temperatures on the biology of some species have been investigated, but little is known about the effects of weather in the field. There have been few quantitative studies on the effects of natural enemies on cereal aphids, but the evidence suggests that they may be important in reducing their numbers. Side-effects of pesticides and fertilisers on aphids are also discussed. Aphids may reduce grain yield and quality. Direct damage may result from reductionsin the number of ears, 1000-grain weight or numbers of grains per ear.  Gramineae are also susceptible to barley yellow dwarf virus, which is transmitted by the aphids.  In  the final section, the possiblities of forecasting cereal aphids are considered.  Cereal aphids will remain a controversial subject until work is carried out on many of the fundamental aspects of their biology.