The U.S. hemp (Cannabis sativa L.) industry, once an important crop for fiber production in the U.S., particularly in the Midwest, has been reemerging in the last decade. In 2024, the hemp production industry was valued at $445 million in the U.S. However, with rapid industry expansion, research has lagged, leaving farmers with little guidance on pest management and cultivar selection decisions. Growers, extension professionals, and researchers in the region have identified three potential main pests in cannabidiol (CBD) hemp: Grapholita delineana, Ostrinia nubilalis, and Helicoverpa zea. In addition to causing physical damage, insect herbivory can increase the production of the secondary metabolite tetrahydrocannabinol (THC), possibly exceeding the legal limit of 0.3%, which would result in the rejection of the crop. This study investigates the damage potential of these borer pests across four cultivars, as well as their potential to change hemp crop cannabinoid content. Larvae counts were taken biweekly and a damage assessment was taken at the end of the season. Using inflorescence samples taken at the end of the season, CBD and THC contents of plants with different damage levels were analyzed using a gas chromatograph (GC) coupled to a mass spectrometer (MS). Data will be collected in summer 2025 and will provide insight into cultivar susceptibility and borer pest pressure, offering growers information for selecting more resilient cultivars and refining integrated pest management strategies in hemp.
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