Optimizing predator-prey dynamics in Southeastern CBD hemp ecosystems via conservation biological control

In the United States, hemp production has surged recently, focusing on its flowering components like cannabidiol (CBD). With CBD widely marketed for wellness, farmers face increasing pressure to reduce pesticide use while managing pests like insects and mites. Our study explored a conservation biological management strategy to address this issue, specifically targeting pests such as Helicoverpa zea, the corn earworm, in outdoor hemp farming. We examined corn earworm predators by analyzing food webs in hemp fields using molecular gut DNA metabarcoding. We aimed to understand predator-prey dynamics in hemp ecosystems by comparing predator gastrointestinal DNA over time. We hypothesized that planting native wildflowers alongside hemp could enhance pollen, nectar, and shelter for beneficial insects, boosting natural enemy populations and reducing pest numbers. Four wildflower species—purple coneflower (Echinacea purpurea), butterfly milkweed (Asclepias tuberosa), yarrow (Achillea millefolium), and black-eyed Susan (Rudbeckia hirta L.) were cultivated individually and in mixed plots at the Organic Farm at Tuskegee University Experiment Station in Tuskegee, Alabama. An untreated control plot without wildflowers was also included. Using a weekly caterpillar damage rating scale from 0 to 5. Biweekly we sampled populations of arthropods using sweep nets. We chose big-eyed bugs for next-generation sequencing (NGS), which allowed bioinformatic analysis to identify prey species DNA in the stomachs of predators. We evaluated the diversity and abundance of predatory arthropods, estimated caterpillar damage, and examined the contents of predators' stomachs. This study assesses how well wildflowers work as part of an integrated pest management strategy for outdoor hemp farming.