Effects of polyethylene mulches on pest management and yield in organic flue-cured tobacco
Management of weed and insect pests in organic production of flue-cured tobacco is challenging due to lack of effective approved control options. Polyethylene plastic mulches are commonly used in vegetable and berry production to manage in-row weed populations, buffer soil temperatures, limit rain-induced soil loss, and maintain soil moisture. Mulch color has been shown to impact plant growth, soil temperature and insect pest populations in vegetable crops. The objective of this study was to evaluate the effects of different colors of polyethylene mulches in organic flue-cured tobacco production. Three trials were conducted in three environments with four colors of polyethylene mulch (red, white, black, and silver) with drip irrigation and bare ground with and without drip irrigation. Light reflectance, soil temperature, aphid population, plant growth, weed emergence, leaf yield and quality data were collected. In 2019, the silver mulch treatment maintained the lowest early season aphid counts (0.68 per plant) compared to bare ground with drip, red, black, and white mulches, which ranged from 4.07 to 6.17 per plant. In-row weed emergence in black, white and silver mulch treatments ranged from 16.7 to 70 seedlings per m2, 170 seedlings per m2 in bare ground without irrigation and 333.3 seedlings per m2 in red mulch treatment. Maximum average soil temperature in bare ground treatments were consistently higher than the silver treatment throughout the entire growing season. Tobacco yield and quality were not different among all treatments except for the red plastic mulch which showed a reduction in leaf yield and quality. Additional data from 2020 trials will also be presented. Under favourable conditions, there is no yield or quality benefit of utilizing polyethylene mulches in flue-cured tobacco production. This is consistent with research in other crops. Given increased weed or insect pest pressure or drought conditions, treatment differences may become more apparent.