dicamba herbicide damage to soybeans

Suspected Mid-South dicamba drift cases picking up

Will incidents continue into July?

It is late June and, once again, dicamba drift is showing up in many Mid-South fields.

“We saw a little bit of dicamba damage back in May,” says Jason Bond, Mississippi State University weed specialist. “For us, the situation then blew up two or three weekends ago. For the last two weeks, calls about dicamba are about all I’ve gotten.

“The damage is in the Delta counties, for sure. We have a lower percentage of Xtend soybeans outside the Delta and, therefore, a lower percentage of treated Xtend soybeans outside the Delta. A few guys have called from farms in the Mississippi Hills. But the majority of my interactions on this have been from the Delta.”

And there are a lot of incidents, says Bond. “At this point, it’s different from last year. Last year, in many cases, I thought you could say, ‘Okay, in this situation, the drift came from north, south, east or west.’ The damaged fields I’m looking at this year involve larger blocks of soybeans with no obvious pattern of what direction the drift came from.

“It seems we’re seeing these big blocks with the majority of the field with the same level of injury. We saw that later in the growing season last year.”

The Bootheel

In a June 21 report (https://ipm.missouri.edu/IPCM/2018/6/dicambaInjuryUpdate/), Kevin Bradley said the Missouri Bootheel had an estimated 25,000 acres of soybeans that had drift damage.

Bradley, University of Missouri weed specialist, was in the Bootheel “about a week ago and I’ve been getting phone calls and messages from the area. I’d say the percentage of Xtend crops there is probably higher than anywhere else in the country. I doubt there’s been such an adoption of Xtend soybean and cotton in such a small geography.

“From what I can tell, though, if you don’t have Xtend soybean, your crop is going to be cupped up from one end to the other. That’s not a surprise because we’ve seen that for the past two seasons.”

It doesn’t take a “super-trained eye to see the tree injury from dicamba. It’s kind of shocking to me to see so much damage to trees.”

Bradley’s views on dicamba drift haven’t changed. “I said it all winter: it’s rarely one thing, but a combination of factors. One of those factors is physical drift. I’m sure there have also been some tank-mix/tank contamination situations. We also have volatility. All the data in front of me says we still have a problem that hasn’t been addressed. It isn’t all operator error like some claim, no way.”

Bradley receives “drift calls from folks who are incredulous and surprised at what’s happened. I’m not — this is the third year of this and I haven’t seen anything that’s worked to keep these products from moving off-site.”

Arkansas

Bradley’s report had Arkansas drift damage estimated at 100,000 acres, says Jeremy Ross, Arkansas soybean specialist.

However, “there are estimates right now that we’re at about 400,000 acres with drift damage.”

See also: Does agriculture need reset key on herbicides?

Bradley’s report “opened some folks’ eyes … but there was at least a week’s lag time between when that number was given (to Bradley) and the report. That means we’ve seen a bunch of damage since then.”

Outside the Delta, Ross is “hearing reports out of Iowa, Illinois, and Missouri. The damage seems to be picking up steam. It’s a shame because we seem to be going the same direction with this we traveled last year.

“Nobody knows what the EPA is going to do with (new dicamba formulation) registration,” which is expected in August. “This is just another black eye for ag — especially in Arkansas. With the (April 15 spraying) ban, the regulations and restrictions we had in place, I figured (the state) wouldn’t see so much drift.”

Louisiana

There are some issues with dicamba drift in Louisiana — although not nearly to the extent as in Arkansas and Mississippi, says Daniel Stephenson, LSU AgCenter weed specialist.

“It started as long as a month ago. For the most part I don’t think it will be yield-reducing. There’s always a danger, though, if there aren’t good growing conditions going forward. Most of the soybeans hit have still been in a vegetative stage.

“Starting last week, though, our soybeans are in reproductive stages and if those are drifted on we’ll be dealing with a different animal. Dicamba on reproductive soybeans is quite damaging even at low doses. That’s the scary possibility going into July.”

There was “a big pocket of off-target damage in the northeast part of the state earlier this season. It’s now begun to occur in the east-central region — east of Marksville down towards Point Coupee Parish.”

There’s also been drift damage in the northwest, north of Shreveport, says Stephenson. “But that’s been 2,4-D damage to cotton. As of (the week of June 18), there were three official complaints about 2,4-D drift. I visited with a farmer last Thursday who was in that situation, but it appears his cotton will grow out of it.

“We’ve also had seven official complaints about Loyant drift. But Loyant isn’t being sprayed on rice anymore. I hypothesize that drift was due to temperature inversions.

“We’re researching low-dose concentrations of Loyant on soybean yields. It’s tough because we’re putting out these low-dose concentrations in 15 gallons of water. That isn’t where drift is — the drift is in much less water and the droplets are more concentrated.”

Tennessee

“We’ve been so darn wet around the state, we’re still replanting,” says Larry Steckel, University of Tennessee weed specialist. “But in the last week, or so, we’ve begun to get reports on drift. After last year, I was hoping we’d be unscathed, but it doesn’t appear that’ll be the case.

“Last week, I was thinking we had something like 2,500 non-Xtend soybeans that had been drifted on. By now, just from talking to county agents and consultants the last few days, I believe that acreage is now up considerably to 9,000 or 10,000.”

The Tennessee Department of Agriculture says “we’re on pace with the number of complaints made last year. The big difference is the majority of complaints are coming from homeowners — cypress trees, tomatoes, gardens, a vineyard. That makes sense because, first, our soybeans are planted later. Second, we’re planting a lot of Xtend soybeans.”

Tennessee has also had some 2,4-D drift on Xtend cotton. “In the last five days, the calls I’m getting have switched from 2,4-D worries to dicamba.”

Going forward

What advice is Bond giving affected growers?

“It’s tough to say what to do. There are three things you have to consider. One is the growth stage the beans are in when they’re hit. Two is the rate that hits the crop. Three is what the weather does for the remainder of the growing season.

“Out of those three, two we have no idea about. Therefore, I can’t say what will happen with the damaged beans.”

Ross says tough economic conditions in farm country are playing a part in the incidents. “Look at everything (growers) are facing. Having this technology in the crop and not spraying dicamba on it is too hard to pass up, I guess. Some of the growers won’t use dicamba but others will. This year, with the weather conditions we’ve had, this is probably the most grown-up mess of weeds I’ve seen. You know, pigweeds are blowing up because they couldn’t get pres activated or getting too many beans planted before the sprayer came across the field.”

It doesn’t help that commodity prices have dropped. “Everyone is trying to do whatever they can to preserve what yield they have. That includes spraying illegally for too many.”

Ross has talked to several seed companies and “they’ve already got their production in for next year. A lot of it is in Xtend varieties. So, will we be right back here next year? What will the EPA say? Will we have the beans and not the herbicide formulations? Those questions have folks responsible for seed production scratching their heads.”

In Louisiana, Stephenson suggests reluctant growers call the Louisiana Department of Agriculture and Forestry (LDAF) and report drift incidents. “I encourage the growers to call, but the last I heard, the (Louisiana) Department of Agriculture hasn’t had any official complaints about dicamba drift. That doesn’t mean it hasn’t happened, but farmers aren’t signing for an official complaint and until they sign, records can’t legally be pulled and investigated from that end.

“I’m told farmers are handling it amongst themselves. I’ve visited fields and helped growers. In Louisiana, (weed specialists) don’t actually investigate drift like they do in other states. The LDAF does that here.

A lot of the calls I’m getting are coming from consultants — ‘Hey, one of my farmers has some dicamba on his beans.’ Then, they’ll send a picture and we’ll talk about the growth stage, what’s happening in the field. Typically, they tell me they haven’t called the (LDAF) and are handling it amongst themselves. ‘They’re marking the damaged areas and are planning on running a yield monitor at harvest. They’ll see if the area that’s damaged yields less than the areas that aren’t and go from there.’”

Steckel says farmers he speaks with aren’t treating dicamba spraying in a nonchalant manner. “The sense I’ve gotten is farmers are worried about drifting dicamba on their neighbors. One call sticks out in my mind. A farmer had pigweed in his Xtend soybeans and he started looking around. He has a number of homes to the east and west of the field and on the north side is cypress trees. He’s got a prevailing southerly wind and after we talked he said he was going to disk the field up and plant LibertyLink beans. He figured the risk of drift was too great.”

TAGS: Weeds
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