Broadleaf Weed Applications

As fall approaches some lawn care professionals shift from an amine form of 2,4-D to an ester form to take advantage of its better efficacy under cooler conditions. In Central PA, one lawn care company applied an ester form of 2,4-D to a home lawn located several hundred feet away from a commercial greenhouse. The ester form of 2,4-D tends to be more volatile than the amine form and on this warm fall day the product volatized and drifted into the side vents of the commercial greenhouse. 

The poinsettia crop in this greenhouse was in a critical stage in its crop development (bract formation) when the application occurred. Within a few days, the greenhouse grower began to notice a slight distortion on the developing bracts. As time went on, the severity of the symptoms increased placing the marketability of this $20,000 crop in jeopardy.

Ester formulations of 2,4-D typically have better efficacy against broadleaf weeds than amine forms, but their increased volatility make them a poor choice when sensitive plants exist in the environment. Lawn care operators who routinely shift to ester forms of 2,4-D in the fall should make sure that their applicators are aware of the risk that their products carry when applied near high tunnels or greenhouses. An alert applicator in this case may have prevented a $20,000 insurance claim.