Evaluation of nonselective herbicides for strawberry termination

Abstract Florida strawberry growers apply the nonselective herbicide paraquat for crop termination. Alternative herbicides are desirable because of recent label restrictions on paraquat use and the occurrence of three paraquat-resistant weed species found in strawberry fields. Field experiments were conducted at the Gulf Coast Research and Education Center at Balm, FL, to compare the efficacy of diquat, paraquat, and glufosinate and determine the optimal rate for strawberry termination. Peak control occurred at 14 d after treatment and strawberry foliage desiccation increased as herbicide rate increased. The highest rate of diquat (2,240 g ai ha−1) and paraquat (2240 g ai ha−1) provided 59% and 79% strawberry control, respectively, and 39% and 77% strawberry foliage desiccation, respectively. The highest rate of glufosinate (2,624 g ai ha−1) provided 82% and 84% strawberry control and desiccation, respectively. Regression analysis determined the rates required to provide 50% strawberry control measured 1,100, 650, and 550 g ha−1 for diquat, paraquat, and glufosinate, respectively, whereas the rates required to provide 80% strawberry control were greater than 2,240 g ha−1 for the first two herbicides and 2,020 g ha−1 for glufosinate. Herbicide rates required to provide 50% strawberry foliage desiccation measured 480, 550, and 330 g ha−1 for diquat, paraquat, and glufosinate, respectively, whereas the rates required to provide 80% strawberry foliage desiccation were greater than 2,240 g ha−1 for the first two herbicides and 1150 g ha−1 for glufosinate. Overall, these results indicate glufosinate is the most effective herbicide for strawberry termination, whereas diquat is the least effective herbicide.