Effect of Flumetralin Applied for Sucker Control in Flue-Cured Tobacco on Sweet Potato Planted the Following Year

Abstract

Field studies were conducted in North Carolina in 2010/2011 and 2012/2013 to determine the effect of flumetralin applied for sucker control in tobacco (Nicotiana tabacum L.) on sweet potato (Ipomoea batatas L. Lam. storage root yield and quality) planted in the following year. Treatments in these studies consisted of flumetralin at 0, 0.67, 1.01, 1.34, 2.02, and 2.69 kg active ingredient (a.i.)/ha applied for sucker control to tobacco 2 weeks after topping (WAT) using a ground sprayer equipped with 3 nozzles per row. In 2012, 3 additional treatments included flumetralin at 1.01 and 2.02 kg/ha applied 2 WAT with a dropline method, and a lay-by treatment of 532 g a.i./ha pendimethalin at 4 to 5 weeks after tobacco transplanting followed by (fb) 1.01 kg/ha flumetralin at 2 WAT (using a 3-nozzle boom sprayer). Sweet potato planted the following year (2011) after tobacco had reduction in no. 1 sweet potato storage root yield in the 2.69 and 2.02 kg/ha flumetralin treatments applied with a 3-nozzle boom sprayer in 2011 and with both application methods (3-nozzle boom sprayer, dropline) in 2013, respectively. Flumetralin application rate (both years) or application method (2013) did not affect jumbo and marketable sweet potato yields. The lay-by treatment of pendimethalin followed by flumetralin in tobacco did not reduce yield (across all grades) of sweet potato planted the following year after tobacco. Overall, these results showed that no concern should exist for sweet potato planted the following year if flumetralin is applied at ≤1.34 kg a.i./ha (label-recommended dose) in tobacco.