Characterizing lepidopteran moth species composition and their impact in floral hemp production systems

Several lepidopteran moth caterpillars cause significant feeding damage to hemp flower buds, resulting in severe economic losses for marketable hemp flowers and cannabinoid biomass yields in Oregon and the Pacific Northwest. Infestations can reduce yields by up to 30% without effective pest control measures. Currently, there is no information on which lepidopteran moth species are the most significant pests in Oregon. Identifying these species based on caterpillars is challenging due to their similar morphological characteristics.

In 2023, we surveyed lepidopteran caterpillars feeding on hemp flowers throughout the season and reared them in the laboratory until they emerged as moths. Our study identified three moth species: corn earworm, false corn earworm, and tobacco budworm, as causing damage to the flowers. Among these, the tobacco budworm was found to be the most dominant, followed by the false corn earworm and the corn earworm. The implications of these findings will be discussed in the presentation. This study is supported by USDA NIFA CPPM and Western IPM Center Grants.