Do polyphagous predators help control orange wheat blossom midge, Sitodiplosis mosellana Gehin (Dipt.,Cecidomyiidae) in winter wheat?

Polyphagous predatory invertebrate populations were manipulated using exclu sion techniques in order to examine their impact on Sitodiplosis mosellana Gehin. Experiments were conducted within the framework: of the LINK Integra ted Farming Systems project in the UK, which allowed the effect of the pred ators to be compared between integrated and conventional farming systems. I n 1995 and 1996, the exclusion technique indicated that polyphagous predato rs had little impact on S. mosellana numbers prior to oviposition, but may reduce the number of midge returning to the soil to diapause and thereby he lp to prevent populations building up in the soil. Sowing date affected ear infestation levels with earlier-drilled, conventionally farmed plots suffe ring heavier infestations. A strong correlation was found between the numbe r of larvae per ear and the percentage of ears infested. At 100% infestatio n there was a mean of 2.8 S. mosellana larvae per ear.