Temporal and spatial population dynamics of corn earworm (Helicoverpa zea) in hemp fields in Delmarva peninsula

Cannabis sativa L., was legalized recently in the U.S. with < 0.3% delta -9-tetrahydrocannabinol content. Following its legalization, hemp cultivation has increased significantly across North America. However, hemp growers have encountered unexpected production challenge and yield loss due to the emergence of the corn earworm (CEW), as a major pest in the Mid-Atlantic and southeastern U.S. Here, we provided three years spatial and temporal population dynamics of CEW, and recommended a possible timeline for pest management. The experiment was conducted to monitor corn earworm-hemp interaction for three consecutive years from July to October in two locations in Maryland. The adult CEW populations peaked from late July through early September and declined toward the end of September. However, the larvae population surged significantly from the end of August until harvest, causing substantial damage to hemp flowers in both locations. These findings provide a timeline for effective pest management strategies, highlighting critical periods for intervention to mitigate CEW damage and enhance hemp yield. The study could serve as a guideline for design more time-effective and efficient pest management strategies to tackle CEW and other lepidopteran pests in hemp cultivation.