Damage Wheat and barley crops that are heavily infested with cereal aphids can suffer losses of up to 30 per cent. Both aphids species can transmit the virus. The proportion of yield loss attributable to each cause varies greatly between seasons and locations. The timing of the infestation determines which is the most affected component. For example, an aphid infestation in late spring during grain filling would mainly reduce grain size.
Some trials suggest that aphids affect different components of yield in different varieties.
Control Several parasites and predators attack cereal aphids. These include ladybirds, lacewings, wasps, hover flies and spiders. However 'bio-control' agents are only effective when the aphid populations are low as they cannot reproduce as fast as the aphids. Spraying with selective aphidicides will encourage the spread of beneficial insects and spiders. Under ideal conditions, when aphids multiply quickly, spraying with insecticides may be necessary.