It can become airborne days after it’s sprayed and drift for miles.

January 23, 2023 1:10 PM

The EPA tells Audubon it “is still reviewing whether over-the-top dicamba can be used in a manner that does not pose unreasonable risks to non-target crops and other plants. Fuller was no anti-pesticide crusader. He sells dicamba and tolerant seeds and thinks farmers should be able to use it except in the heat of summer. When the [Arkansas State Plant] board received a record number of dicamba-related complaints in 2017, he joined the unanimous vote to ban spraying after April 15.
posted by spamandkimchi (14 comments total)

I'm generally in favor of both GMOs and judicious use of pesticides, but yes, this seems pretty clear-cut. If the stuff can't be relied upon to not drift into other fields and/or non-cultivated land, it shouldn't be used.
posted by Joakim Ziegler at 1:12 PM on January 23, 2023 [1 favorite]

...Monsanto not only expected the devastation, it also leveraged it as a sales pitch, telling farmers to plant Xtend seeds to protect their crops from dicamba drift...
...Court records show Monsanto scientists struggled to prevent it from vaporizing and drifting in their tests, and the company didn’t make its herbicide available for independent testing before it went to market...
...The devastation, which can easily cost a grower six figures, is driving farmers who don’t use dicamba to plant engineered crops. The EPA says only about half of the dicamba-tolerant seeds planted in 2020 were treated with the herbicide...
..Long hardened against glyphosate, Palmer amaranth began showing resistance to dicamba quickly after Xtend seeds hit the market. In 2021 Illinois researchers documented resistance in waterhemp, another prolific pigweed. Troublingly, the study plants had never been exposed to dicamba. This type of adaptation threatens to render weeds immune to multiple herbicides and any that might be developed in the future.

GMOs that increase yield, reduce water needs, or increase nutritional content are all fantastic things. Pesticide resistant GMOs are a plague, and this is the outcome. And the outcome will be the same when dicamba resistance is so high that they have to design the next one. And the next one. Until there are no forests, and no bugs, and no birds. Just soybeans, cotton, and hogweed.
posted by hydropsyche at 2:49 PM on January 23, 2023 [5 favorites]

hydropsyche: I think you might be exaggerating a smidge. If this stuff didn't readily vaporize, it wouldn't be a huge problem. In itself, herbicide resistance in weeds isn't a problem beyond, well, the weeds being resistant, which just means you can't use those herbicides on them, which just brings you back to square one. Also, glyphosate, for instance, doesn't kill trees, bugs, or anything like that, it kills a type of grasses that happens to include some common weeds that compete with crops, so basically, herbicide resistant crops combined with the application of herbicides is precisely a way to increase yields and reduce water needs.

Also, you can't have it both ways. Either the herbicide kills a lot of stuff, and thus upsets the ecosystem, or lots of plants quickly develop resistance, and the herbicide is ineffective. Glyphosate, at least, doesn't really absorb into plants through the roots, only through the leaves, so it's not a big deal to have it in soil, where it also breaks down pretty quickly.

Generally, though, it may be better to genetically engineer plants to be pest-resistant themselves. This is the case with Bt cotton, which is modified to produce Bt toxin, an insecticide, as part of the plant. This is similar to how plants themselves develop defenses against pests, and it's been very effective.
posted by Joakim Ziegler at 4:06 PM on January 23, 2023

Glyphosate is a broad spectrum herbicide that kills both monocots (grasses) and eudicots (broad leafed plants). You might know it as Round-Up, which many people use to kill poison ivy as well as any blade of grass that dares to grow in a sidewalk crack. Glyphosate resistance is a problem across the board, and dicamba resistance is coming right along. Dicamba is less toxic to grasses and is considered a eudicot (broadleaf) herbicide but, as the article notes, it has this fun property of vaporizing under high temperatures.

Herbicide resistance occurs through two mechanisms: the evolution of herbicide resistance through natural selection on weeds, and through cross pollination, herbicide resistant genes can spread to only vaguely related plants.

Killing of whole oak trees, as dicamba is doing in the article, absolutely has the potential to impact bugs that eat oak trees and birds that eat those bugs, as described in the article.
posted by hydropsyche at 4:22 PM on January 23, 2023 [8 favorites]

Though it was depressing, thanks for sharing this article.
posted by misskaz at 4:32 PM on January 23, 2023

There I was, minding my own business, taking my pesticide recertification training, and suddenly two pesticide reps offered us training to get a special certificate in Dicamba application. Although I am unlikely to ever apply Dicamba, there was no way to avoid this and still hand in my codes giving me credit for the rest of the classes. It quickly became apparent that Dicamba blowing offsite was a real problem that this certificate was meant to defuse. Like, I imagine if you have this certificate, the person whose land was contaminated can't sue the company, because they have proof you were given proper training on how to apply it. So they sue you.
posted by acrasis at 4:47 PM on January 23, 2023 [3 favorites]

hydropsyche: "Herbicide resistance occurs through two mechanisms: the evolution of herbicide resistance through natural selection on weeds, and through cross pollination, herbicide resistant genes can spread to only vaguely related plants."

Yes, but again, this isn't a problem in itself, it just makes the herbicide useless, so you're back to where you were if you were never going to use that particular herbicide in general.

And yes, Dicamba drifting the way it does does seem to be a major problem. But that's not really a problem with most other herbicides, and not a problem with herbicide-resistant crops in general.
posted by Joakim Ziegler at 5:05 PM on January 23, 2023

Herbicide resistance can be a problem for a number of reasons. Herbicides are important for fire control along roadsides and under powerlines and control of things covered with thorns and things like poison ivy, oak, and sumac, giant hogweed, wild parsnip, and others that cause severe skin rashes when people touch them. Giant hogweed, one of the main weeds dicamba is being used to fight in Arkansas, is incredibly difficult to remove from farm fields once it's established. Trying to dig or plow it up will break tools. Again, it causes a terrible rash if your skin touches it. Herbicides and fire are about the only things we have against it. Removing one of our only tools to control it in the name of making farming (temporarily) easier (until it develops resistance to the herbicide, as it already has to glyphosate and is now working on for dicamba) is an incredibly short-sighted approach.

As noted in the article, integrated pest management approaches are much more effective long term and are the recommendation of scientists not being paid by chemical companies. That means, for example, monitoring, using mechanical approaches, and using targeted pesticides only when and where necessary, reducing the risk of herbicide (insecticide, etc.) resistances developing so we don't have to keep inventing new, more dangerous tools because the old ones stopped working.
posted by hydropsyche at 5:30 PM on January 23, 2023 [5 favorites]

We've seen truly insane declines in bird populations in grasslands, far outpacing also-horrifying declines in most other biomes. There's scattered evidence of insect collapse, especially drawing attention to the fact that we mostly have no idea what's going on with insects, but where we have been able to measure, it doesn't look good.

/Something/ is going radically wrong in our ecosystems. It may have a lot to do with neonicotinoid pesticides. And it also may have a lot to do with simple large-area mono-cropping, combined with strategies of eradication for everything but the monocrop.

"this isn't a problem in itself, it just makes the herbicide useless, so you're back to where you were if you were never going to use that particular herbicide in general."

The top ten common reactions to herbicide resistance are all increasing the amount of herbicide. And indeed the point of GMC roundup-ready crops is to increase the amount of roundup that one can apply. This leads to more bioaccumulation of the chemicals, and unknown downstream effects. This stuff matters; over-fertilization has given us the dead zone in the gulf of mexico. Everything counts in large amounts.
posted by kaibutsu at 9:55 PM on January 23, 2023 [4 favorites]

The idea that any herbicide, insecticide, fungicide, pesticide, rodent killer is surgically precise, that its breakdown products are inert, that it has no impact on anything but the stuff you don't like is a faith incompatible with survival.

We are dosing the worlds most productive farmland in a cocktail of materials. Randomized controlled double blind trials conducted by multiple independent research institutions with these chemicals on humans, on every animal and plant in the ecosystem before its use: no of course not. Just sell them, buy a boat and let your grandkids inherit the wind... or lymphoma or asthma or famine.

It used to ve that the Ratio of GMO for herbicide/insecticide : GMO for nutrition, disease prevention, drought heat tolerance was the same as the ratio of Ducks to Unicorns but now that Golden rice has actually been grown (checks notes) on 100 acres, its just the ratio of Ducks to Ducks that had animated tv shows about them.

With this kind of amazing PR progress, we'll be drinking aquacola in no time.

Source: former organometalic ligand chorehand turned organic farm hand turned hermit.
posted by anecdotal_grand_theory at 10:55 PM on January 23, 2023 [2 favorites]

Also, we already knew glyphosphate killed things, including workers. we are learning now that even in doses common over years of food eating that it elevates cancers in humans.

Even hydrophobic and immobile chemicals will have a small fraction migrate into drinking water.

We are trying to use big fat chemical markers on tissue paper and we are shocked, SHOCKED, when the ink bleeds through. We are staining the earth for decades and centuries.
posted by anecdotal_grand_theory at 10:58 PM on January 23, 2023

GMOs that increase yield, reduce water needs, or increase nutritional content are all fantastic things. Pesticide resistant GMOs are a plague, and this is the outcome.

Pesticide resistant GMOs do increase yield, that's why farmers use them.
posted by atrazine at 4:54 AM on January 24, 2023

Yes, but again, this isn't a problem in itself, it just makes the herbicide useless, so you're back to where you were if you were never going to use that particular herbicide in general.

The likelihood that - gene transfer of herbicide resistance, or bio distribution/accumulation of herbicide or its metabolites/breakdown products - is going to be somehow beneficial? Negligible

The likelihood that it's gonna fuck stuff up in the wider environment? Much, much greater.

This is classic tragedy of the commons stuff, and needs to be regulated out of existence.

Source: me. Synthetic chemist, worker for the eeevil chemical industry.
posted by lalochezia at 6:24 AM on January 24, 2023 [3 favorites]

Great article and info on herbicide spread.

Kaibutsu, re: insect collapse, you may find Silent Earth interesting. He covers all theories of what is causing the mass die off of insects in a fair manner, even including the Rumsfeldian, "unknown unknowns".

In one part he describes a day in the life of a bee, which encounters all the listed risks; pesticides, exhaust, invasive diseases, monoculture, etc, and it's amazing that anything survives.

In the sections covering neonics he mentions persistence in the soil and drift, but the details escape my memory, and since it was an audio book borrowed from a library, I sadly cannot find the relevant info. But it was interesting.

My favorite anecdote was about midges. How many people complain about the little pests. How Queen Victoria even cancelled some outdoor event to avoid them. Yet as much as we may wish all midges dead, it turns out they pollinate cacao flowers, so they give us chocolate.
posted by ecco at 8:30 PM on January 24, 2023 [1 favorite]