Patterns of cereal aphid infestation in autumn and implications for Barley Yellow Dwarf Virus control

Abstract

One of the most serious threats to cereal crops is Barley Yellow Dwarf Virus transmitted by cereal aphids. With the current ban on neonicotinoid seed dressings, applications of foliar applied insecticides are likely to increase. There is no treatment threshold and aphids are difficult to assess within the crop. The use of yellow sticky traps was explored as a way of monitoring levels of immigrating winged aphids and for measuring aphid infestation patterns within fields. Transect of sticky traps extending from the crop edge up to 70m into the field were deployed up and downwind of two common field boundaries, woodland and hedgerows. Most Sitobion avenae were deposited within 10m of the crop edge regardless of boundary type or orientation of the wind. Twice as many Rhopalosiphum padi were caught adjacent to hedgerows compared to woodland and more were caught in the headland area of the field compared to 35m from the crop edge and beyond. The considerable variation between and within fields in aphid infestation levels suggests that within-field monitoring is needed and would help reduce insecticide usage.