Review of Preplant-Incorporated Pesticide Evaluations in Mississippi Sweetpotatoes

The use of insecticides incorporated into the soil prior to planting (preplant incorporated, or PPI, application) and approximately 30 days post planting (layby-incorporated, or LBI, application) is a recognized control regimen to reduce insect damage to sweetpotato roots in Mississippi. Seventeen compounds with potential for use as soil-incorporated insecticides were tested in small-plot research trials from 2001 to 2009. Efficacy was evaluated by counting insect feeding scars on marketable roots at harvest. Results within each trial were converted to percent control values based on the water-treated check plots. Results ranged from negative percent control values (more damage than found in the water-treated plots) to nearly 70% reduction in percentage of insect damaged sweetpotatoes.