The use of field margins in the manipulation of parasitoids for aphid control in arable crops

摘要

Parasitoids are one of the key natural enemies of aphids on arable crops. Ecological studies in cereal crops have highlighted the importance of early season synchrony between colonising aphids and their parasitoids for preventing the development ofeconomically damaging aphid populations in the summer. To promote this synchrony, a strategy has been devised based on the manipulation of natural parasitoid populations using aphid sex pheromones. Laboratory and small-scale field studies of parasitoid foraging behaviour have shown that female aphid parasitoids from a range of economically important species respond strongly to plant-derived aphid sex pheromones and that the presence of pheromones have the potential to greatly increase levels of parasitism in aphid populations. It is proposed to use the pheromone to establish overwintering parasitoid reservoirs in field margin strips, which will be designed to provide suitable hosts and winter shelter. Some of the field margin options being promoted incurrent agri-environment schemes to encourage biodiversity could provide suitable habitats for the parasitoids and for other beneficial insects, giving an added, positive benefit for the farmer. This parasitoid manipulation strategy is being tested on commercial fields as part of a SAPPIO Link research project beginning this year.