Abstract
Potential negative impacts due to herbicide drift or sprayer contamination is a cause of major concern for sweetpotato (
Ipomoea batatas
L.) producers that was made more urgent by commercialization of crops tolerant to application of glufosinate and 2,4-D-choline. Field studies were conducted in 2020–21 to assess impacts of reduced rates of combinations of glufosinate with 2,4-D-choline on sweetpotato growth and production. Reduced rates of 1/8×, 1/10×, 1/33×, 1/66×, 1/100×, 1/128×, or 1/256× of a 1× rate of both glufosinate at 0.655 lb a.i./acre (32 oz/acre) plus 2,4-D-choline at 1.064 lb acid equivalent/acre (32 oz/acre), simulating those encountered in drift or sprayer contamination events, were applied to ‘Orleans’ or ‘Bayou Belle’ sweetpotato at 10 or 30 days after transplanting to simulate growth stage encountered when applications may occur adjacent to corn, soybean, or cotton. Glufosinate in combination with 2,4-D-choline can cause significant visual injury to sweetpotato at rates often encountered in drift or sprayer contamination events. Negative yield impacts resulting from this injury were generally greater at high rates (1/8×, 1/10×, or 1/16×) when application occurred 10 days after transplanting and with all rates when occurring at 30 days after transplanting. Negative environmental conditions not conducive to optimal sweetpotato growth, such as low moisture or extreme temperatures, can affect plant ability to recover from initial herbicide injury.