Insect community composition in Pennsylvania industrial hemp crops: Implications for sustainable pest management

Industrial hemp (Cannabis sativa L.) is a new crop in Pennsylvania since 2019. A critical challenge for hemp c=ultivation is the lack of specific pest management strategies and pesticide restrictions. Understanding the composition, and the impact of prevalent insect pests and natural enemies on hemp crops is crucial to structure sustainable control programs and avoid detrimental effects. In 2022, we conducted weekly insect samplings through the growing season to determine the abundance and diversity of species inhabiting fiber/grain and CBD cultivars, compare community compositions, and evaluate herbivore damage levels in regional cultivars. Herbivores were the most abundant (90%) and less diverse insect functional group for both CBD (Shannon index = 1.813) and fiber (Shannon index = 4.168). The cannabis aphid, P. cannabis was the most prevalent pest (86%) followed by generalist thrip species, Thrips tabacci, Frankliniella sp., and Neohydratothrips sp. (3.7%), chrysomelids such as flea beetles Altica sp. and Crepidodera sp., and cucumber beetles, Diabrotica undecimpunctata (2.8%), and leafhoppers (1.8%). Natural enemy communities were more diverse and evenly distributed (Shannon index: CBD=10.07, fiber=6.27). Coccinellidae species (Coleomegilla maculate, Propylea quatuordecimpunctata, Harmonia axyridis) were the most abundant biological control agents (28%), followed by arachnids (26%), anthocorids (15%), ants (7%), hoverflies (6%), lacewings (6%), and parasitic wasps (6%). The composition of insect species significantly varied between CDB and fiber cultivars (F= 5.6232, p=0.001). We present levels of herbivore damage on hemp cultivars. These results highlight the importance of preserving natural enemies and developing pest management that leverages biological control in Pennsylvania hemp crops.