Supporting natural pest control in hemp with native wildflowers

Biological Conservation Control (CBC) is a sustainable pest management strategy that strengthens natural enemies such as predators, parasitoids, and entomopathogens. Unlike classical or augmentative approaches that introduce new species, CBC supports those already present in the ecosystem. This could be a valuable strategy for hemp (Cannabis sativa L.) production, where pesticide use is restricted by residue limits and consumer concerns, and CBC contributes to crop protection and sustainability by reducing chemical inputs and promoting ecological interactions. This study investigated a CBC strategy for suppressing corn earworm (Helicoverpa zea) in outdoor hemp by enhancing floral resources that support natural enemies. We hypothesized that interplanting native wildflowers adjacent to hemp plots would attract beneficial arthropods, suppress pest populations, and reduce crop damage. Four wildflower species—purple coneflower (Echinacea purpurea), butterfly milkweed (Asclepias tuberosa), red/pink yarrow (Achillea millefolium), and black-eyed Susan (Rudbeckia hirta L.) were planted in monocultures and mixtures, with hemp-only plots as controls. The experiment was conducted at the Tuskegee University Experiment Station in Alabama. Arthropods were sampled weekly with sweep nets and biweekly with pitfall traps and yellow sticky cards. Weekly bloom counts were recorded with a clicker to track the total number of plants and blooms. Corn earworm abundance and feeding damage were assessed weekly on five randomly selected hemp buds per plot using a 0–5 severity scale. At harvest, hemp yield was measured. This research shows that native wildflower plantings can strengthen IPM in hemp and support sustainable crop protection.