Wind‐modulated landscape effects on colonization of B russels sprouts by insect pests and their syrphid antagonists

Most crop fields are annually cleared, including arthropod populations. Recolonization depends on the source habitat presence in the landscape and often is affected by weather conditions. The present study identified source habitats and the effects of temperature and prevailing wind direction on colonization of B russels sprouts by pests and their natural enemies. We sampled arthropods on standardized monitoring plants in 18 landscapes with different areas of potential source habitats. Most abundant pests and antagonists were A leyrodes proletella , B revicoryne brassicae , P lutella xylostella and syrphid larvae. Variation in A . proletella colonization was best explained by the upwind area of oilseed rape (positive effect) and temperature (negative effect). Variation in B . brassicae colonization was best explained by the downwind area of oilseed rape (positive effect), whereas no effects on P . xylostella were found. Syrphid colonization was affected by prey abundance only (positive effect). The results of the present study suggest that A . proletella was transported downwind, whereas B . brassicae located host plants during an upwind flight for approximately 1 km. This is remarkable for aphids with often limited upwind flight ability. Consideration of prevailing wind directions improves forecasting of the colonization intensity by pests from important source habitats.