Pesticide Drift
Grapes are particularly sensitive to growth regulator herbicides, such as 2,4-D and dicamba, which are widely used in corn and soybean production. These products can injure the vines, significantly reduce yields and contaminate the fruit even at extremely low rates. The most common symptoms of pesticide exposure include distortion of leaves and stunting of leaves and shoots (Figure 1 and Figure 2).
Figure 1. Fan-shaped leave distortion commonly caused by 2,4-D damage to grapevines. Photo from Purdue Extension
Figure 2. Cupping of leaves and distortion of shoots commonly caused by dicamba damage to grapevines. Photo from Purdue Extension
What can you do?
Applicators can reduce the risk of off-target damage by avoiding spraying herbicides past early May. After that, applicators should consider applying only non-volatile products, such as glyphosate. Some options for grape growers to avoid problems include 1) planting grape varieties that are less sensitive to growth regulators 2) selecting sites that are isolated from crop fields and/or 3) planting windbreaks.
Driftwatch is a voluntary communication tool that enables crop producers, beekeepers, and pesticide applicators to work together to protect specialty crops and apiaries through the use of mapping programs. Driftwatch communicates the presence of your vineyards, orchards and/or other herbicide sensitive crops to commercial applicators and adjacent farms. There is no fee to register your site.
Sign-up as a specialty crop producer here
Sign-up as an applicator here
For more information on herbicide damage to grapes, see ‘Watch Out for: Grapes’ by Dr. Bruce Bordelon: https://www.extension.purdue.edu/extmedia/HO/DW-10-W.pdf