Stuck in the Dicamba Cloud

You can stop using a certain chemical on your crops, but you can't necessarily stop your neighbor from using it on theirs. And you have even less control over the wanderings of the chemical clouds floating up from their fields.

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Not everyone wants to buy Monsanto’s creations. It comes down to a matter of economics.

Organic and non-GMO farmers make money by ignoring seed technology and growing what their customers want, or some farmers simply shun the newest technology for something less pricey.

Other farmers grow fodder for less discerning commodity markets where yield and production are all that matters. That difference is at the heart of a controversy in Middle America where Monsanto’s newest miracle, dicamba-resistant Xtend soybeans are grown.

Successful genetic modification of plants led researchers to create glyphosate (Roundup) resistant corn, soybeans, cotton, alfalfa, and canola. That resulted in an over dependence on glyphosate by farmers, and resistance verging on immunity of several weed species glyphosate once controlled.

Farmers needed a new herbicide. That’s when Monsanto was able to patent dicamba-resistant soybeans and cotton.

First registered in 1967, dicamba is a 50-year-old herbicide that forces broadleaf plants to grow themselves to death. It’s what the industry calls a growth regulator—a synthetic plant hormone. Leaves of plants exposed to dicamba show a characteristic curling or shriveling of the outer edges giving them a cupped, puckered appearance due mostly to the fact that plant cells continue multiplying and growing even when they shouldn’t.

Dicamba has pucker power.

Though it is safe for grassy species, it can be deadly to broadleaf plants if allowed to come into contact with seed, germinating seed, or newly pollinating seed embryos. It can kill the germ of life in almost any plant. Most plants (not just weeds) considered “broadleaves,” including ornamentals, trees, and other oil seeds grown in cropping areas of the United States, are susceptible (except for grass and grass crops, though even those can be damaged at certain growth phases) to dicamba damage.

Soybean and cotton crops lacking Monsanto’s patented gene, vegetable crops, ornamentals, and trees have low-to-no tolerance of dicamba. They’re at risk to temperature inversions combined with wind that can relocate plant damaging vapors for miles around or maybe just from the field alongside.

Normal, non-puckered soy plant.

Here’s how.

Dicamba is volatile, meaning that when sprayed in liquid form onto fields to control pesky weeds it can evaporate into a gas that sometimes forms a “cloud,” a little like morning mist rising from the land. Only you can’t see it. You can’t smell it. And you may not recognize its effects for up to weeks after its been applied.

It may even be weeks before the cloud floats away. When it comes into contact with plant tissue it is immediately absorbed.

With talk of being a possible carcinogen, it sounds almost sinister to outsiders, but protecting corn crops from weeds with 2,4-D dates back to the mid 1940’s. 2,4-D and its cousin dicamba are included in weed control formulations used on urban and suburban lawns today. Anyone who’s had a lawn treated to control broadleaf weeds like dandelions, has used some if not all of the 2,4-D family—including dicamba.

These are called organic compounds (pertaining to a class of chemicals including carbons) first used by agriculture to control weeds on pastures, and in fields of cereal crops and corn. They are dangerous to fish and aquatic life, but 2,4-D is considered safe for use to control weeds in fruit orchards and around other trees so long as it isn’t applied directly to the trees.

Dicamba is not so ‘benign’. That‘s why Missouri‘s largest peach grower is suing Monsanto after two years of dicamba damage to his orchards.

For one thing, dicamba persists longer than 2,4-D, which makes it a natural choice for farmers who want herbicide activity to remain for a time so that weeds emerging after application will also be controlled. Dicamba does that. And farmers like herbicides that also kill germinating weeds and germination in weed seeds. Dicamba can do that, too.

But that power is what has allowed even special “safe” formulations of dicamba to damage off target plants. New generation dicamba herbicides were supposed to have reduced volatility to eliminate off site movement and subsequent damage.

It appears that the stability of new dicamba formulations may have been overestimated.

So far, the level of damage over the last three years related to farmers planting Xtend soybeans has led to states of Tennessee, Arkansas, and Missouri placing a hold on dicamba applications. Missouri was last to implement the hold, and second behind Tennessee in lifting it. Now soybean and cotton farmers in those states who are able to demonstrate special need for dicamba can once again apply it to their fields.

Missouri Ag Director Chris Chinn said in a press release, “From the moment the stop sale and use order went into effect, we’ve been working to get these weed control products back into the hands of our farmers. BASF, Monsanto and DuPont (makers of ‘safened’ dicamba) came to the table and agreed to additional safeguards for product use in response to issues we’ve faced this growing season.”

The safeguards Director Chinn speaks of are similar to labeled parameters of application in effect prior to the ban. What changed was special need permission, requiring applicators to be in possession of a special needs label at the time of application, and limited application times from between 9:00 in the morning to 3:00 in the afternoon.

Missouri and Tennessee have, on the whole, been much more accommodating to dicamba use than Arkansas, where protecting susceptible crops in latter stages of reproductive development have taken precedence over stricter labeling. To date there have been over 600 complaints in Arkansas.

Application bans there remain in effect.

Applicators I’ve spoken to are baffled by the number and extent of damages. One told me he’d followed every rule and made some new ones of his own about when application should be acceptable but was receiving complaints in spite of that. And then there are applicators like the one who sprayed a neighbor’s soybeans in a 20 mile per hour wind (not according to label right up to the edge of a private residence) who said he thought, “It would be all right.”

Potted plants and trees in the front yard, next to a child’s swing set and swimming pool, curled from dicamba exposure almost the same day.

But one of the most difficult tasks farmers and homeowners face if they have damages from herbicide drift like that of dicamba is assigning liability. Research has shown dicamba vapor can travel up to three miles, and symptoms may not manifest themselves for weeks after application. Crops with herbicide injury aren’t covered by crop insurance, and proving who was responsible and recovering damages is a little like having a hit and run on your car in the parking lot at Walmart.

That is best illustrated by a phone call I received last week. Many farmers and pesticide applicators in Missouri have been getting similar calls

Caller ID gave me the name of an out of state farmer whose family owns land in Missouri. We hadn’t spoken for years. After perfunctory greetings—long time no see— he got to the nitty-gritty.

“My soybeans in the field north of the highway are puckered. I think they have dicamba damage. I was wondering, what did you spray on your soybeans across the highway from mine?” he asked.

Richard Oswald is a fourth-generation farmer from Langdon, Missouri. He is president of the Missouri Farmers Union.

 

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