State officials in Illinois, Iowa and Tennessee have received hundreds of complaints blaming the weedkiller dicamba for damage to oak trees this summer, says the Midwest Center for Investigative Reporting (MCIR). Usage of dicamba — and complaints of crop damage — has increased with the release of soybean and cotton varieties genetically modified to tolerate doses of the chemical.
In Illinois, retired biologist Lou Nelms “has documented damage to oak trees across the state from dicamba,” and in Tennessee, the state agriculture department “investigated and confirmed complaints that dicamba had damaged oak trees at the state’s largest natural lake,” reports MCIR. The Iowa Department of Natural Resources “has received more than 1,000 complaints about oak tree damage from unknown pesticides, some of which cited dicamba as a cause.”
Monsanto says the most likely cause of crop damage is improper use of dicamba. It disputes researchers who have suggested the chemical is too temperamental for use on row crops despite new, low-volatility formulations that are supposed to stay where they are sprayed and not damage neighboring fields.
“Herbicide drift is a familiar problem for farmers. What happened this summer, though, was unprecedented in its scale,” says NPR. “Dicamba damage was reported all over the Midwest and mid-South, from Mississippi to Minnesota. Farmers filed thousands of complaints. They reported damage to tomato fields, watermelons, fruit trees and many other crops.” Growers argue over who should pay for damage to crops. Trees and wildflowers also are affected, as are the pollinating insects, such as honeybees, that rely on them, said NPR.
The EPA is considering additional restrictions on where and how dicamba is applied. The Arkansas State Plant Board has proposed a ban on use of dicamba on cotton and soybeans during the growing season next year.