Landscape composition influences the abundance of asparagus beetles

Pest management of arthropod pests has often been focused on a local scale, frequently relying on the application of insecticides and other within field management strategies. However, the surrounding landscape can also play a major role in pest suppression of cropping systems. In this study, we conducted a multi-scale study focused on the effect of landscape structure on the common asparagus beetle, Crioceris asparagi, an important pest of asparagus (Asparagus officinalis). Asparagus beetle occurrences were surveyed in 2019-2020 from eleven asparagus fields in Michigan (2019: 7 fields, 2020:10 fields). Generalized Linear Mixed Models (GLMM) were used to analyze the response of the pest to landscape composition and configuration indices at different spatial scales. Results demonstrated that the landscape composition through the effect of proportion of semi-natural habitat (deciduous forest, evergreen forest, grassland) positively influenced asparagus beetle abundance. We found that landscape configuration through the effect of increased edge density and Shannon's Diversity Index negatively affected asparagus beetle abundance. While previous studies have demonstrated that an increase in landscape complexity often leads to lower pest populations, this study found that semi-natural habitats can support key pest populations as well.