Our study is the first to demonstrate that the biocontrol service provided by generalist predators in north-central U.S. soybean fields is dependent on the diversity and composition of the surrounding landscape.
Biological control of A. glycines is reduced in simple landscapes dominated by corn and soybean production. Members of the Coccinellidae, an important family of natural enemies of A. glycines, were also found to decline in soybean fields located in agriculturally dominated landscapes. Therefore, maintaining overall landscape diversity, and especially perennial grassland
and forested habitats, in the landscape will favor suppression of soybean aphid. Moreover, these habitats may also enhance biocontrol services in other crops because the generalist natural enemies found in soybean fields are also important antagonists of many other herbivores.
Our results suggest that such non-crop habitats do not need to directly border agricultural
fields to promote biocontrol services; we found that occurrence of these habitats within ;1.5 km explained the highest percentage of the variation in both biological control and coccinellid abundance.