Field assessment of the effects of deltamethrin on polyphagous predators in winter wheat

In the south‐west of England, cereal aphids can spread barley yellow dwarf virus and reproduce during winter. Ground‐living polyphagous predators may be important in controlling these active cereal aphids. This 2‐year study investigated the effect of deltamethrin on predator numbers, using pitfall traps. A randomised block design was used in an area of winter wheat (cv. Aquilla) in which deltamethrin‐treated and control plots were surrounded by polyethylene barriers. Pitfall catches of polyphagous predators were reduced by about 30% in the treated plots compared with the control plots.