Is Herbicide Drift Coming to the Mid-Atlantic?

Concerns for plant growth regulator off-target crop injury are on the rise. What will we experience here in the Mid-Atlantic this summer?
Is Herbicide Drift Coming to the Mid-Atlantic? - News

Updated: July 19, 2017

Is Herbicide Drift Coming to the Mid-Atlantic?

Soybean showing cupped and crinkled leaves on July 17 at our Rock Springs Agronomy Farm.

Last week, we wrote an article about the reports of 2,4-D drift to off-target crops from burndown applications that took place this spring. Over the last two weeks, we have been hearing about the dicamba drift complaints that have been taking place in the Mid-South. A number of news articles have been posted about potential drift including 140 complaints in Missouri of suspected off-target dicamba drift, nearly 600 complaints in Arkansas, 55 in Mississippi, and 77 in Tennessee. These numbers are already old and outdated and likely now much higher. Drift complaints in the North have been fewer, but perhaps we are just moving into the timeframe where we are beginning to see some issues. Just yesterday, we observed a soybean field at our Rock Springs Agronomy farm that started showing some dramatic PGR symptoms. It's not obvious how this occurred or whether it is a result of particle or vapor drift, but it's certainly the result of a plant growth regulator herbicide applied in or near the field.

In the South, we are hearing about the illegal use of older dicamba formulations as part of the problem as well as other application issues. Dr. Bob Hartzler at Iowa State University wrote a nice article this past week about some of the differences between the Mid-South and the Midwest cornbelt that helps explain why the risk for off-target movement is greater in the south. These included

  1. The longer growing season which results in a longer planting period and application period for herbicides
  2. Different cropping systems that include both dicamba-resistant varieties of soybean and cotton and a greater opportunity for dicamba use
  3. And of course the prevalence of Palmer amaranth leading farmers to treat dicamba-resistant crops with POST-applied dicamba.

As Palmer amaranth and waterhemp increase their distribution into the Mid-Atlantic region will we see a similar trend? Arkansas, Missouri, and Tennessee have all enacted new rules for the dicamba herbicide use in commercial agriculture. Below is a summary of what these three states have enacted with Arkansas being the most restrictive. Time will tell whether we will be moving in that same direction here in the Mid-Atlantic region.

Arkansas - The sale, use, or application of dicamba containing pesticides is prohibited starting July 11, 2017 for 120 days except for products packaged in containers of one quart or less. The ban is for agriculture use only, with an exemption for pastures and rangeland (which includes use on lawns, gardens, and turf). There is an increase in civil penalty for dicamba misuse of up to $25,000.

Missouri - Lifted initial dicamba ban and initiated Special Local Needs labels for Engenia, Xtendimax, and Fexapan. These new application restrictions include 1.) Do not apply during winds speeds greater than 10 mph, 2.) Do not apply before 9 am or after 3:00 pm, 3.) All applications must be made by certified applicators, 4.) Applicators must complete an on-line web-based form titled "Dicamba Notice of Application" prior to the actual application, and 5.) Applicators must keep and maintain a record of use for each application.

Tennessee - Must be a certified applicator. Older dicamba formulations are prohibited for the remainder of the season. Dicamba may only be applied from 9 am - 4 pm, and application of dicamba over the top of cotton after first bloom is prohibited.

Authors

William S. Curran, Ph.D.

Annie Klodd