Well, since May has come around again, the annual calls on herbicide drift have been pouring in. Row crop fields are being burnt down in the wind and drift has been the main call to my phone for the last 2 weeks.
This is a recurring problem in our state resulting from the high degree of crop diversity we have out there. Severity depends on the chemicals used and the extent of coverage.
Here are some points on herbicide drift to keep in mind from a 2014 blog post around the same time of year.
If growers have had herbicide drift injury occur on their trees, they should first contact their county agent and take photos for documentation. The next step is to contact the neighbor from whom the drift originated and contact the neighbor’s insurance agency to notify them the incident occurred.
Once everything has been documented it is usually a wait and see situation because of the high degree of variability from one case to the next.
Often with glyphosate, glufosinate, paraquat, and flumioxazen, the injury is more cosmetic than economic unless there is extensive coverage, leading to significant leaf and flower/nut loss. Quality may also be affected if extensive foliage damage occurs because the trees must expend energy to re-grow new foliage.
The only way to know the extent of damage for sure is to evaluate the crop at the end of the season. Repeated injury, of course, will lead to more serious losses and can cause long term damage to the trees.