Cover crop to aid biological control: Exploring costs and benefits to apple orchards

Cover crops can provide a myriad of benefits to apple orchards such as supporting pollination, increasing nutrient cycling, preventing erosion, and promoting biological control. In contrast, they can shelter vertebrate pests, like voles and mice, and insect pests that may damage trees. To better understand the trade-offs for cover crops in orchards, we investigated how cover crop mixtures benefit pollinators and biological control, and their potential to increase mammalian and arthropod pest activity. In the WVU cider orchard, we planted three replicates of an alfalfa hay cover crop mixture, a native wildflower cover crop mixture, and replanted the existing orchard grass cover crop mixture that had been established in 2016. Once established, we measured pests and predator biological control. Giving-Up-Density traps were used to determine vertebrate pest activity. We measured potential aphid and leafhopper pests within the cover crop by using yellow sticky cards. Epigeal predator community was examined by deploying pitfall traps. We used bee bowls to gauge pollinator abundance. The results of this study highlight the benefits of cover crops to pollination and biological control, best cover crop layout, which cover crop to use in apple orchards, and what pests are exacerbated by using a cover crop. This study will provide a guideline for what cover crop mixtures increase pollination and protection, while limiting the presence of vertebrate pests.