Volatility of Broadleaf Weed Herbicides When Applied to Turfgrass

Laboratory and field studies were conducted in 2010 and 2011 to evaluate the volatility of commonly used turfgrass broadleaf herbicides when applied to tall fescue (Lolium arundinaceum Schreb.). Herbicides were applied at the highest label rate for dandelion (Taraxacum officinale G.H. Weber ex Wiggers) control. Turfgrass flats treated with herbicides were placed in enclosures containing tomato plants. In laboratory experiments, tomatoes exposed to turfgrass treated with products containing amine formulations of synthetic auxin herbicides exhibited minimal injury, but exposure to products containing low-volatile ester formulations caused significant negative effects on tomato quality, epinasty, and callus formation. Generally, products containing low-volatile ester formulations of synthetic auxin herbicides exhibited less volatility, compared to 2,4-D butyl ester (volatile standard). A subsequent field study corroborated the laboratory results, although injury symptoms were less severe. Turfgrass managers should avoid herbicides containing low-volatile ester formulations when vulnerable non-target plants are nearby, and/or when environmental conditions such as high temperature favor volatility.