Annual Strawberry Response to Clopyralid Applied During Fruiting

As the amount of methyl bromide approved for use in Florida strawberry diminishes, growers are faced with a forced transition to alternative fumigants. Many of these methyl bromide alternatives have been associated with reductions in weed control, requiring additional but complementary measures. POST herbicide options for annual strawberry are limited, resulting in significant portions of the strawberry acreage in Florida being hand-weeded when troublesome weeds escape conventional control methods. Strawberry has shown acceptable tolerance to clopyralid in other areas and production systems; however, its integration into the Florida production system and ramifications of applications during fruiting warrants further research. Eight trials were conducted, with three common strawberry cultivars grown in West Central Florida subjected to POST spray and drip-tape-injected applications of clopyralid. Formation of new strawberry leaves was not affected by clopyralid application, except for a reduction in new leaves of the cultivar ‘Strawberry Festival' at the highest rate of application of 261 g ae ha−1 in comparison with the nontreated control. Strawberry leaf malformation was best explained by an exponential growth equation, whereas marketable yield followed the trend of a Weibull peak. At the maximum labeled rate (66 g ha−1), leaf malformation was less than 5% for all cultivars tested, and marketable yield was estimated at 104% of the nontreated control. Nomenclature: Clopyralid; strawberry; Fragaria × ananassa Duchesne. Al reducirse la cantidad de methyl bromide aprobada para el uso en la producción de fresas en Florida, los productores deben enfrentar una transición forzada a fumigantes alternativos. Muchas de estas alternativas a methyl bromide han sido asociadas con reducciones en el control de malezas, requiriéndose así medidas complementarias. La fresa ha mostrado una tolerancia aceptable a clopyralid en otras áreas y sistemas de producción. Sin embargo, su incorporación en los sistemas de producción de Florida y lo que esto podría implicar para las aplicaciones durante la producción del fruto requiere más investigación. Se realizaron ocho ensayos con tres cultivares comunes de fresa producidos en el Centro Oeste de Florida y que fueron sometidos a aspersiones POST y a aplicaciones inyectadas a través de la cinta de goteo con clopyralid. La formación de hojas nuevas de la fresa no fue afectada por la aplicación de clopyralid, excepto por una reducción d