Landscape Effects on the Abundance of Apolygus lucorum in Cotton Fields.

Resource-continuity over spatial and temporal scales plays a central role in the population abundance of polyphagous pests in an agricultural landscape. Shifts in the agricultural land use in a region may alter the configuration of key resource habitats, resulting in drastic changes in pest abundance. Apolygus lucorum (Meyer-Dür) (Hemiptera: Miridae) is a pest of cotton in northern China that has become more serious in recent years following changes in the region's cropping systems. However, no evidence from the landscape perspective has yet been gathered to account for the increasing population of A. lucorum in China. In this study, we investigated the effects of landscape composition on the population abundance of A. lucorum in cotton fields in July and August of 2016, respectively. We found that increased acreage planted to cotton actually had a negative effect on the abundance of A. lucorum, while planting of other crops (e.g., vegetables, soybean, and peanut) was positively associated with the mirid's population abundance in cotton fields. Maize production only displayed a positive effect on population abundance in August. Our results suggested that the decreasing of cotton area may weaken the trap-kill effect on A. lucorum, and the extension of other crops and maize potentially enhance the continuity of resources needed by A. lucorum. Combined effects of these two aspects may promote an increased population density of A. lucorum in the agriculture district. In the future, when possible, management strategies in key regional crops should be coordinated to reduce resource continuity at the landscape or area-wide scale to lower A. lucorum populations across multiple crops.