As 2,4-D and dicamba off-target injury reports start to trickle in across the South and Midwest, weed scientists and regulators are urging growers to stay on label.
Texas cotton growers are seeing more 2,4-D damage to cotton than is normal this time of year, Texas A&M Extension Cotton Specialist Gaylon Morgan told DTN. University of Tennessee Extension weed scientist Larry Steckel is also fielding reports of 2,4-D injury in cotton in western parts of the state, as well as at least one dicamba injury report, he said.
According to the American Association of Pesticide Control Officers (AAPCO), dicamba injury complaints have been filed in Arkansas, Indiana, Iowa, Missouri and Oklahoma, primarily on non-soybean plants such as trees, ornamentals, fruits and vegetables.
Applicator confusion about spray buffers is a likely cause of the 2,4-D damage in Texas, Morgan said. “If there is susceptible crop downwind from your field, you cannot spray when the wind is blowing in that direction — there are no buffers that allow you to spray,” he said. “I think that is the single biggest misunderstanding out there.”
Steckel suspects rainy weather has forced Tennessee growers to squeeze applications in during tiny windows of time, including during temperature inversions. “There simply being no good day to spray has been the biggest problem here,” he said.
Keeping dicamba and 2,4-D in your field is more critical than ever as postemergence spraying picks up in Xtend soybeans and continues in Enlist cotton in the weeks ahead, Morgan warned.
“With this technology, whether Enlist or Xtend, there is a learning curve with how to keep things on target,” he said. “Individuals who have done it are learning that you have to follow every single step on that label to keep it on target.”
So what should you do if you suspect 2,4-D or dicamba injury in your fields? Morgan and Steckel have some recommendations.
1. KNOW THE SYMPTOMS
Soybeans are extremely sensitive to dicamba, and cotton is extremely sensitive to 2,4-D, but those aren’t the only potential victims of herbicide drift. Fruits such as grapes and tomato are also very sensitive to these herbicides, as well as many vegetables, ornamentals, trees and other plants.
For the most sensitive crops, it only takes tiny amounts of the herbicide to cause visible injury. For example, just 10 to 16 drops from an eyedropper of dicamba, dispersed over an acre, could cause visible injury symptoms on crops such as soybeans and grapes, according to research from the University of Georgia.
A young soybean plant with dicamba injury will have distinctive cupped and curled leaves on new growth. In reproductive stages later in the season, soybeans tend to show damage with curled or aborted pods, and dead flowers.
A cotton plant exposed to 2,4-D will show injury called “strapping,” where the leaves become long and narrow, and the leaf veins run parallel to each other, Morgan said.
“It is in the new growth that the symptoms become very pronounced,” he explained. “How long the symptoms are observed depends on the rate of herbicide. If it is a very, very low rate, the symptoms may be present for a couple of nodes … then normal-shaped leaves begin to appear. If the rate is higher, the symptoms may continue to be observed season-long on the new growth.”
The University of Arkansas has compiled photos to help identify herbicide injury here: https://plants.uaex.edu/….
2. IDENTIFY THE SOURCE AND REPORT THE PROBLEM
Start by figuring out where the herbicide came from. Don’t forget to include yourself in the list of culprits, Morgan noted. Tank contamination or applicators in the wrong fields are not uncommon mistakes this time of year.
If you suspect a neighbor, inform them immediately, so they know not to spray that herbicide again under the same conditions, Steckel said. While young soybean and cotton plants can outgrow early season herbicide injury without yield loss, a second drift incident can do much more serious damage.
Enlist and Xtend cotton growers have the option to make additional passes with glufosinate rather than dicamba or 2,4-D, Steckel added. See details on this option here: http://news.utcrops.com/….
Whenever possible, try to work out any damage concerns and compensation with your neighbor first, before moving on to other legal action, Morgan recommended.
3. MAKE SOME CALLS
If fence-row talks break down, it may be necessary to get more professional help. Contact your state Extension agent for a second opinion, Morgan said. And you can file a complaint with your state department of agriculture, most of which are on alert for this type of injury this year.
You can also report the damage to the manufacturer of the herbicide in question. For problems with Enlist herbicides, use this Dow AgroSciences’ number: 800-992-5994. For complaints regarding Monsanto’s XtendiMax herbicide, you can call this hotline: 1-844-RRXTEND. BASF recommends contacting a BASF retailer or representative or using this website to report problems with their Engenia herbicide: www.Non-Performance.BASF.US. For FeXapan, the label states that problems should be reported to a local DuPont representative or retailer.
Finally, Steckel recommends giving your insurance company a heads up that injury has occurred.
4. DOCUMENT THE PROBLEM
Take detailed, time-stamped pictures of the damaged crop and record everything you know about the incident, such as the weather conditions, location and acreage affected. Keep in mind that dicamba injury takes anywhere from seven to 21 days to show up; 2,4-D injury is usually visible in seven to 10 days, Steckel said.
“Document the injury over time, too,” Morgan added. “Injury from low rates of 2,4-D will grow out in two weeks, but injury from higher rates, the ones more likely to cause yield loss, could last three to four weeks.”
You can take samples of the damaged plant and send them in for chemical analysis, or have a state investigator do so.
“Ultimately, the only way to determine the level of economic loss is to see the yield at the end of the season,” Morgan said.
He recommends marking the affected acres so that you can examine any differences on the yield monitor during harvest.
See an article from Morgan on the drift incidents in Texas here:
Emily Unglesbee can be reached at Emily.firstname.lastname@example.org.
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