Field research was conducted in 2012 and 2013 in Georgia, New York, and North Carolina to evaluate the effect of trifluralin PPI on turnip root production. Treatments included trifluralin PPI at 0, 0.42, 0.56, 0.84, 1.12, 1.68, 2.24, and 3.36 kg ai ha-1. Aboveground injury to turnip varied by location and increased from 0% to 85% as trifluralin rate increased from 0.42 to 3.36 kg ha-1. Trifluralin at 0.42 to 0.84 kg ha-1 caused ≤7% injury, except at Clayton, NC, and Freeville, NY, where injury ≤32%. Trifluralin at 0.42 to 0.84 kg ha-1 reduced turnip root yield ≤11% at all locations, except Clinton, NC, where yield was reduced 29% and 43% by 0.56 and 0.84 kg ha-1, respectively. Turnip roots were not injured internally by trifluralin. Our research results suggest that up to 0.84 kg ha-1 trifluralin PPI is safe to use in turnip roots.
Nomenclature: Trifluralin; turnip, Brassica rapa L. ‘Purple Top White Globe’