CORESTA Congress, Berlin, 2016, Agronomy/Phytopathology Groups, AP 36

Spinosad and cyantraniliprole residues in flue-cured tobacco

North Carolina State University, Dept. of Crop Science, Raleigh, NC, U.S.A.

From 2013 to 2015 research was conducted to establish the maximum expected pesticide residue on cured tobacco that would result from a maximum labeled application rate and minimum pre-harvest interval of specific active ingredients. Residues of two insecticides, cyantraniliprole and spinosad, were quantified on flue-cured tobacco produced in six environments in North Carolina during the research cycle. Treatments were applied to flue-cured tobacco grown on research stations near Kinston and Rocky Mount, North Carolina. Tobacco was managed according to North Carolina Cooperative Extension Service recommendations and harvested four times by stalk position. Pesticide residues on cured leaf were determined by Global Laboratory Services, Inc. in Wilson, North Carolina. Data were analyzed and reported by individual year, location, active ingredient, and stalk position; with primings one and two represented in the “lower” stalk position (Lug + Cutter), priming three represented in the “middle” stalk position (Leaf), and priming four represented in the “upper” stalk position (Tip). Cyantraniliprole residue was below the limit of quantification for all stalk positions in all six environments. Spinosad residue, as either one of or combinations of spinosyn-A and/or spinosyn-D, was only recorded in the lower stalk positions of all Kinston environments. Spinosyn-A residue was consistently greater than spinosyn-D, with the highest means for each being recorded at 1.128 and 0.231 mg/kg, respectively, in the Kinston 2014 environment. Ultimately, it appears that cured leaf residues from either of these active ingredients are likely to be extremely low across a variety of environments relative to other pesticides with established Guidance Residue Limits.