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Carlton, CO | http://entweb.clemson.edu/pesticid/saftyed/24Ddrift.htm
Herbicide volatility
All herbicides can drift as spray droplets, but some herbicides are sufficiently volatile to cause plant injury from drift of vapor (fumes). For example, 2,4-D or MCPA esters may produce damaging vapors, while 2,4-D or MCPA amines are essentially non-volatile and can drift only as droplets or dry particles.
Vapor drift occurs when a volatile herbicide changes from solid or liquid into a gaseous state and moves from the target area. Herbicide vapor may drift farther and over a longer time than spray droplets. However, spray droplets can move over two miles under certain environmental conditions so crop injury a long distance from the intended target is not necessarily due to vapor drift. A wind blowing away from a susceptible crop during application will prevent damage from droplet drift, but a later wind shift could move damaging vapors from the treated field into the susceptible crop. An experiment conducted in Canada demonstrated that 3 to 4 percent of both 2,4-D amine and high volatile ester drifted out of the target area as spray droplets. However an additional 25 to 30 percent of the ester drifted as vapor in the first 30 minutes after spraying while no additional movement of the amine was detected (7). | |
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Ester vs Amine
