Antixenosis and tolerance to Helicoverpa zea (Lepidoptera: Noctuidae) in industrial hemp cultivars

Corn earworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) is a polyphagous insect pest that attacks several crops of agricultural importance including industrial hemp (Cannabis sativa L.; Rosales: Cannabaceae). Corn earworm is often the insect that is most damaging to hemp, tunneling into maturing flower buds and developing seeds and feeding on leaves. Corn earworm control relies on insecticide treatments which may result in ecosystem contamination, insecticide resistance, and other problems. This research aimed to identify industrial hemp cultivars that express antixenosis to corn earworm feeding on leaves, as well as to determine the resistance levels of the cultivars. To evaluate antixenosis, 8 industrial hemp cultivars were tested for corn earworm feeding preference in free-choice and no-choice tests. The cultivars were ‘Southern Tiger’, ‘Southern Sunset’, ‘Cat Daddy’, ‘Southern Luck’, ‘Sweet’, ‘Cherry Dwarf’, ‘Citrus’, and ‘BaOx’. The results are presented, and the ecological and pest management significance of the results are discussed.