For a number of (selective) herbicides, the manufacturers state recommendations and restrictions on use. Thus e.g. state to spray the product on dry crops, at high humidity and within certain limits of the ambient temperature. This is still understandable. But it is also already mentioned not to spray the product in an east or north wind. What is the reason behind this (wind direction) restriction?
Answer
The answer is not obvious. There is a suspicion that with such wind it is mainly about lean/drying little growing weather with low relative humidity (RH), where uptake of herbicides can be quite disappointing because of, among other things, thicker wax layers built up in the crop surface and faster drying of spray liquid with less absorption to consequence (for more explanation, contact Prof. De Cauwer, expert UGent).
Answered by
dr. ir. Pieter Spanoghe
Crop protection
http://www.ugent.be
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