This note takes exception to the Reisinger and Robinson (1976) hypothesis of long-distance transport of 2,4-D in sufficient quantities to damage grapes after first putting the overall problem of herbicide injury in central Washington in its proper perspective. What little is known about the threshold concentration for 2,4-D damage is reviewed, and the causes of ambiguity in and the detailed technical objections to this paper are outlined. It is pointed out that equally plausible, simpler hypotheses include the fact that it took several months for regulatory controls on 2,4-D application to become effective, that the sources for the reported injury can probably be found in the large quantities of 2,4-D applied within 15–30 km of the grapes, or that other chemicals may be responsible for at least part of the problem.

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