How does Round-Up drift from a farmer’s spray rig affect a Bradford pear tree?
The Gardener’s Answer
Hello, Mark: Round-Up is a broad-spectrum herbicide used by many gardeners and farmers to kill unwanted weeds. The main ingredient of this product is glyphosate, which is absorbed through the foliage and eventually to the root system, killing the unwanted grass/weeds. Unfortunately, this product is not selective in terms of what it damages. This is why when we use this product we must be careful only to spot spray and do not use on windy days. If Round-Up is sprayed on a windy day, it can potentially drift to plant material that it was not intended for. I am not sure how close your tree is planted in relation to where the Round-Up was sprayed, but I would not think that your Bradford pear tree would have been subject to high concentrations of the weed killer. If your ornamental pear did come into contact with Round-Up, the foliage would look burned and eventually drop. This can certainly cause stress on your tree, but unless it was directly sprayed on your tree I think it will be fine. You can always take a sample of the damaged foliage to your County Cooperative Extension Service for them to diagnose. It is difficult to determine the extent of the damage without seeing the tree.