2017 ASHS Annual Conference

Bicyclopyrone (BIR) is a new 4-Hydroxyphenylpyruvate dioxygenase (HPPD)-inhibitor that is being evaluated for use in sweetpotato. BIR would be the first HPPD-inhibiting herbicide to be approved for use in sweet potato. Previous studies have shown that sweet potato varieties may differ in their response to herbicide inputs. A greenhouse study was conducted in Charleston, South Carolina to evaluate BIR tolerance in 6 sweetpotato varieties.  Five commercial varieties (Covington, Beauregard, Excel, Sumor, and Bayou Belle) and one experimental sweetpotato line (04-136) were propagated in the greenhouse.  Cuttings from the sweetpotatos were transferred to herbicide treated soil. BIR was applied to the soil at rates of 50, 100, and 200 g ai/ha. Data were taken on bleaching, general phytotoxicty, and fresh weights.  Generally, application of 50 g ai/ha of BIR did not have any phytotoxic effects on the sweet potato varieties; however, numerically weights of the plants trended to decrease when comparing 50 g ai/ha to the untreated check. When accessing injury and bleaching at higher rates Beauregard trended to be the most tolerant while Sumor was the least tolerant to BIR. The 04136 experimental line did not show any phytotoxic symptoms at the 1X rate; however this variety lost the most fresh weight relative to the untreated check when 200 g ai/ha of BIR was applied.