Droplet and Vapor Drift from Butyl Ester and Dimethylamine Salt of 2,4-D

The relative drift of droplet and vapor of butyl ester and dimethylamine formulations of (2,4-dichlorophenoxy)acetic acid (2,4-D) was determined under conventional crop spraying procedures in the field. Labelled herbicides were mixed with spray solution or emulsion, and the ground deposit and the air-borne droplet and vapor clouds drifting from the target area were collected. The mass of the dimethylamine formulation drifting as droplets was 3 to 4% of the material sprayed. No significant amounts of this material were collected as vapor or particulate drift. For the butyl ester, in addition to the droplet drift, 25 to 30% of the material was collected as vapor drift in the half hour after spraying. Thus the drift potential from the butyl ester was about 8 to 10 times greater than that from the dimethylamine formulation under the conditions of these tests.