Strawberry Tolerance to Bed-Top and Drip-Applied Preemergence Herbicides

Broadleaf weeds and nutsedge are persistent problems with limited management options for strawberry growers in Florida. Experiments were conducted in 2012 to 2013 (year 1) and 2013 to 2014 (year 2) at the Gulf Coast Research and Education Center in Wimauma, FL, to evaluate tolerance of two strawberry cultivars ('Strawberry Festival' and 'WinterStar'(TM)) to PRE herbicides applied on the bed top or injected through the drip tape. The bed-top herbicides were applied to formed beds following fumigation but prior to laying the plastic mulch. Herbicides evaluated included two rates of EPTC, fomesafen, halosulfuron, and S-metolachlor as well as tank mixes of EPTC + S-metolachlor, fomesafen + S-metolachlor, and napropamide + oxyfluorfen. Drip-applied herbicides were applied through a single drip tape and strawberries were transplanted 1, 7, 15 and 30 d following application. Drip-applied herbicides included two rates of EPTC and fomesafen as well as two rates of a tank mix of napropamide+oxyfluorfen. None of herbicides applied on the bed top except S-metolachlor 214 g ai ha(-1) consistently injured either strawberry cultivar or impacted yields. None of the drip-applied herbicides damaged the strawberry plants or reduced yields at all planting dates. In year 1, EPTC at 229 g ai ha(-1) and EPTC at 229 g ha(-1) + S-metolachlor at 107 g ha(-1) resulted in a 70 to 86% reduction in purple nutsedge density compared to the nontreated control. No differences in nutsedge density among treatments were observed in year 2. The herbicides evaluated are safe for use on strawberry and would provide growers with alternative herbicide options, application timings, and application techniques. Further research is needed to evaluate efficacy. Nomenclature: EPTC; fomesafen; halosulfuron; napropamide; S-metolachlor; purple nutsedge, Cyperus rotundus L.; strawberry, Fragaria X ananessa Duchesne 'Strawberry Festival' and 'WinterStar' (TM)