Selectivity and efficacy of clopyralid on strawberry (Fragaria X ananassa)

Field experiments were conducted in 2001 through 2003 in Wooster, OH, to determine strawberry (Fragaria X ananassa) plant response to clopyralid applied after plant renovation in established plantings. Clopyralid applied at a rate of 200 g ae/ha or greater controlled at least 82% of common groundsel (Senecio vulgaris) 6 wk after treatment (WAT). Maximum total fruit yield (marketable plus unmarketable fruits) occurred at a clopyralid rate of 200 g/ha, and higher or lower rates resulted in reduced yield. Application of clopyralid at 400 g/ha tended to reduce the canopy of the strawberry crop, especially in comparison to rates lower that 200 g/ha. Overall, clopyralid applied POST at 200 g/ha did not reduce fruit yield when applied after strawberry renovation, and effectively controlled common groundsel plants that were entering the reproductive stage.