Assistant Extension Professor of Entomology North Carolina State University Raleigh, North Carolina
In response to the proposed FDA mandate on lowering tobacco alkaloid concentrations, our study investigates the implications of varying alkaloid levels on pest infestations and the agronomic properties of tobacco leaves. Alkaloids like nicotine, produced by tobacco plants as a natural defense, could influence insect herbivory and disease prevalence. This study aims to quantify pest pressure and assess cured leaf characteristics across different tobacco genotypes with varying alkaloid levels. We are evaluating ten tobacco genotypes, representing burley, flue-cured, and dark tobacco, to understand the relationship between alkaloid concentration, pest resistance, and cured leaf quality. The trial will be conducted at one location with six replications per genotype. Insecticide and fungicide treatments will be withheld, ensuring natural pest and disease pressures are observed. Weekly monitoring will document flea beetle infestations, injuries, and thrips numbers using image capturing and imaging processing instead of traditional in situ counts. Using images made insect sampling more accurate and facilitated injury estimation during the early season 4-5 weeks post-transplant. This is an ongoing trial, and we expect the low-nicotine varieties will have a significant effect (positive or negative) on the level of pest infestation compared to the traditionally grown high-nicotine varieties. Results will be finalized in summer 2024. Our research fills a significant gap in understanding how alkaloid concentrations affect pest dynamics and tobacco quality, providing valuable insights for growers and the global tobacco industry. The outcomes will inform breeding programs and cultural practices to optimize tobacco production under new regulatory constraints.