What's up with all the dead branches on trees in the region?

My name is John Batteen. I'm the IT Manager at Natural Abundance in Aberdeen, SD, and a remote software developer. I'm currently building the next version of the software that runs Natural Abundance and about 70 other cooperatively owned grocery stores nationwide.

I grew up and currently live on a farm near Cresbard, SD. My dad unfortunately had to quit farming due to health problems when I was only 8, and the land has been rented out ever since. However, my immediate family and my uncle and cousin remain interested in, invested in, and committed to agriculture in South Dakota. I'm working towards farming the land again myself some day.

I've had health problems since I was a baby and have been on lots of medication all my life. I was always interested in how it worked. I studied chemistry at the South Dakota School of Mines & Technology for two years with the intention of getting into drug design before my career took a different path. I continue to study chemistry and pharmacology on my own time. Herbicides are just drugs for plants, so the chemistry is very familiar to me.

You may have noticed around town and around the countryside, there are many trees with isolated dead branches, and some dead trees scattered about. It's a strange pattern of damage. Sometimes we'll see something similar as a result of drought, but there hasn't been much drought here the last two years and the problem is getting worse.

It's a result of herbicide application to row crops, specifically dicamba and 2,4-d. Dicamba was approved for over-the-top application in row crops starting in 2017, and that's when this problem began, but the effects are cumulative. The herbicides are systemic, meaning the plant transports them through its vascular tissue all throughout the plant no matter where it's absorbed. However, it is preferentially translocated to the growth tips which is why the damage concentrates there with a nonlethal dose. You may wonder, how does it get from the field all the way to the middle of town? That's a long way for spray to drift. It evaporates off of the fields for days after being sprayed. The University of Missouri proved in 2019 that dicamba can be detected in the air up to 72 hours after application following the label directions, probably longer, but they didn't keep measuring. (Five Things We've Learned About Dicamba, April 19, 2019, University of Missouri) You may wonder, why are the trees not all dead? Well, some of them out in the country where they get higher doses are. But the doses they are getting are far below the doses being applied to the field. What we're seeing in trees is a result of chronic low-level exposure, rather than a single high dose.

You may wonder, why is it only some trees? If it's in the air, surely everything is getting more or less the same dose. Damage is worse in immediate proximity to fields but by and large it's widespread, but intermittent. The reason is, sensitivity to herbicides varies dramatically not only between species, but also within members of the same species. When this issue first cropped up, I reported damage to my windbreaks to the Department of Agriculture. They came out to survey the situation, and they took samples from both a damaged and an undamaged tree. The undamaged tree had lower levels of dicamba than the damaged tree, but actually had higher levels of 2,4-d. That specific individual was just less sensitive to the chemicals.

I noticed that elms in particular showed the worst damage when only dicamba was being applied. Since 2019 when 2,4-d use also became widespread and dicamba use shrunk slightly, I started noticing damage to Russian olives and boxelders. Boxelders in particular show the damage very vividly before it actually causes substantial mortality to the tree. When you see boxelders where most of the leaves are dark but the leaves on the last 18 inches or so of the growth tips are lighter colored and all frayed looking, that's 2,4-d damage. Russian Olives don't get deformed leaves, they just look wilted. Grape vines are also highly susceptible. I worked in the grape industry in Minnesota and moved back to the farm where I grew up in Faulk County in fall of 2016 to start a commercial vineyard. Most of the grapes I planted are dead. None of them are producing. It's not the cold. These same varieties are being grown in Montana and North Dakota.

So far as I can tell, conifers are nearly unaffected, as are cherries, apples, gingkos, and others. Some species show deformed leaves but otherwise seem to keep growing mostly fine like elderberries. Some species have normal or mostly normal looking leaves, but just an unusually small number of them, like oaks and Russian olives. Grasses are naturally not affected by even a full dose of either dicamba or 2,4-d, as they are strictly broadleaf herbicides. The sensitivity of native annuals seems to vary widely, with some species displaying deformed leaves but growing otherwise normally and other species showing no signs. Even with smaller trees, damage seems to be not as bad lower to the ground, so I think ground level vegetation like weeds and grass isn't getting as much as the tall trees, but I'm not sure.

The chemical companies knew the problems that would arise from dicamba and 2,4-d. This is proven in the BASF internal emails released as part of the discovery process from the Bill Bader peach farm lawsuit in 2019. Bill Bader's peach farm in Missouri suffered dramatically from dicamba drift when the product was first released, and he successfully sued the manufacturers. "The one thing most acres of beans have in common is dicamba damage. There must be a huge cloud of dicamba blanketing the Missouri Bootheel. That ticking time bomb finally exploded! The scope of the damage is on a massive scale and fingers are pointing in all directions from grower to grower. It will be interesting to see how all the complaints are handled." (Jason Roberts, Innovation Specialist Report, Missouri Bootheel, July 4, 2016, BASF)

Soybeans are extremely sensitive to dicamba, and before resistant genetics were widespread, dicamba-damaged soybeans were all across the nation. Even today, if you go look at a test plot, you will see certain rows with cupped and crinkled leaves. Those particular varieties do not carry the resistant trait. The worst part is the link between these chemicals and cancer. 2,4-d applicators have a statistically significant increase in the rate of thyroid cancer versus the general population, and we're all 2,4-d applicators now.

In a different way, these herbicides are problems for farmers too, so the problem may solve itself. We learn when we get our pesticide applicator license that following the label rates is extremely important. A full dose application will kill all of the plants. A half dose application will kill some, perhaps even most plants, but the plants that survive contain genes that are partially resistant to the herbicide. Repeated non-lethal exposure to herbicides in plants that reproduce every year like weeds leads to rapid evolution of herbicide resistance.

All of the weeds in the region right now, sprayed or not, are being exposed to chronic low levels of herbicide. The ones by the field edges are getting that "perfect" amount for evolving resistance, enough to cause substantial damage but not enough to be lethal. And indeed, the field edges where these weeds are spreading in from the outside are typically the worst looking parts of the field. It took twenty years for weeds to evolve resistance to glyphosate. Last year was the fourth year of over-the-top application of 2,4-d and already I saw quite a bit of resistant kochia. This year, there are some atrocious looking bean fields out there. Glufosinate still works for now, but even then, it's a contact herbicide, and if you wait too long to spray, the weeds will come back from the stems. Our fields this year have quite a bit of dicamba and 2,4-d resistant kochia that got sprayed too late with glufosinate and is coming back from the stems.

The chemical companies know this, which makes me suspicious that there are no better options coming down the pipeline and this spray-based weed control gravy train we've all been riding for the last twenty-five years may be coming to an abrupt end soon. From the internal email linked earlier, "Pigweeds are still an issue, but most herbicide options are about to get exhausted and the next step is either live with them in the field or hire chopping crews."

This is not the farmer's fault, and this is not an anti-agriculture article. My family makes their living from farmland in Faulk and Edmunds counties. Farmers were told that the product was safe to use, that it would not do this. The EPA should have known that this would happen, but they approved the product anyway. In 2020 the Center for Biological Diversity successfully sued the EPA, and the legal approval for dicamba was vacated. The next year, the EPA re-registered dicamba for use in row crops, but with added restrictions on when farmers could spray. These restrictions against spraying past a certain date or above a certain temperature were intended to minimize evaporation, but it didn't work. Damage continued, and the Center for Biological Diversity again successfully sued the EPA, and earlier this year the legal approval for dicamba was again rescinded.

That would be the end of the problem, except for the fact that in 2019 the EPA approved 2,4-d for over-the-top application in row crops, and it is also volatile. Luckily, it isn't as volatile, however, it is more difficult for plants to metabolize. It will be interesting to see what the situation on the ground looks like next year with only 2,4-d being applied over-the-top and not dicamba. There is a similar lawsuit against the EPA over the 2,4-d registration ongoing, but it may be a year or more before we know the outcome.

Bayer and Syngenta have both re-submitted to have dicamba again legal for application, but this time with even more restrictions. The Bayer proposal would only allow application up to planting, and the Syngenta proposal would allow application through the V2 growth stage, or up until June 12th, whichever occurs first. It remains to be seen whether that will be enough to make a substantial difference. Those submissions will almost certainly not be approved in time for application in 2025.

That's a good question, and I honestly don't know. Inventing new chemicals is out of our hands. It would be the dust bowl around here if we tried to go back to tillage for weed control. We could turn it all back to pasture, but the success of row crops in this region is the primary reason why we are as wealthy as we are. The economic results of that would be disastrous. Other than the weed control issue, this is a truly ideal location for row crop agriculture and it would be a shame if it came to an end. If I had to guess, the answer comes from robots killing weeds mechanically or with lasers or something. Carbon Robotics just released a commercial product this year. There are about 100 that they've built so far currently in operation. It can only cover 20 acres a day, but it's a start. (Onion grower turns to laser tech to battle weeds) Another company called AIGEN just had an article in the Mitchell Republic about their autonomous weed-killing robot. (New AI-powered robot taking farm fields by storm) Toro the tiller company is working on one too. In any case, don't be mad at the farmers. They're doing the best they can with what they have, and we all need to eat. Perhaps our best course of action is ensuring our young people have the very best educations we can give them in the STEM fields and agriculture. We have to innovate our way out of this somehow.

I believe this is a Japanese lilac, downtown Aberdeen by the Sherman

Not sure what kind of tree this is, west of Central Park, downtown Aberdeen

A young oak just east of Central Park, downtown Aberdeen

A collection of sad trees between the fire station and Central Park, downtown Aberdeen

I'm not sure what kind of tree this is, Central Park, downtown Aberdeen

Dead branches up top with healthy growth on suckers from the bottom is a sure sign of damage to most or all growth tips on a plant. Insects could do this, you could do it with a scissors, but the deformed leaves on the growth tips are a sure sign that this is herbicide damage.

These are cottonwoods on 391st Avenue south of Moccasin Creek golf course, and a good example of varying susceptibility to damage within individuals of the same species.

This is a silver maple in a private residence near Moccasin Creek. It doesn't look bad from far away, but the next picture reveals damage close up.

This frayed appearance to the leaves is characteristic of 2,4-d. Dicamba tends to make a more cupped shape with crinkled edges.

One of our bean fields. The dead plants are dicamba and 2,4-d resistant kochia that got sprayed with glufosinate. Up close, a lot of them are coming back from the stem. Behind them in the tree rows, the yellow leaves on the tops of some trees and the dead branches visible are a result of herbicide damage.

Dicamba and 2,4-d resistant kochia that got sprayed too late with glufosinate coming back from the stems.

Some of the especially sensitive Siberian elms in this picture are dead.

More dicamba and 2,4-d resistant kochia that got sprayed too late with glufosinate coming back from the stems.

Some of the especially sensitive Siberian elms in this picture are dead.

The damage to this grape vine is subtle, but visible in the frayed or jagged looking edges, and the wrinkled appearance to the leaf.

This is a morning glory. The next pictures will show deformed leaves close up, but the herbicides appear to affect their ability to climb. They can't figure out which way is up and they just grow in a big heap. They're starting to grow out of it and will eventually grow up the ladder, but they should be way high by August. The same thing happened last year with them being confused until late July or early August. I haven't grown them in South Dakota up until last year, but in Minnesota, they definitely did not do this.

This cupped morning glory leaf is from herbicide damage.

A boxelder displaying the characteristic dark colored healthy growth and light colored damaged growth.

Up close of damaged boxelder leaves.

Russian olives, some with dead branches, some dead.

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