As new technologies spurred a boom in use of the weed killer dicamba, complaints of damage to crops on neighboring farms overwhelmed the Missouri Department of Agriculture.
The department is asking the Missouri General Assembly for help to get a handle on the complaints, which have grown into a backlog of nearly 600 cases of alleged dicamba misuse that have been investigated, but are still waiting for a ruling.
Before the dicamba boom, the department handled 75-85 complaints a year for pesticide misuse. It received more than 1,000 complaints from 2017-19, mainly for damage caused by dicamba. The department investigates those complaints to determine if damage was caused by someone not following the instructions on the dicamba label.
The state's backlog of cases waiting for a determination went from zero in 2017 to 595 at the end of last year. The backlog means the department is trying to catch up with complaints made years ago. It hasn't completed any investigations into complaints from 2018 or 2019. The department is asking for four additional investigator positions to add to its current crew of 10, and two case review specialists, a new position.
Dicamba has been around since the 1960s, and until a few years ago, it was mainly used in the winter and early spring to control broadleaf weeds before planting. In 2015, the USDA approved Monsanto's dicamba-resistant soybean and cotton seeds, and the EPA followed over the next two years by approving dicamba formulations that could be sprayed over the top of dicamba-resistant crops during the growing season.
After that, producers used more dicamba, and used it during the growing season. Weed-killers don't always stay where they're sprayed, and across the country, dicamba sprayed on one farm walked over to other fields, damaging non-resistant cotton, soybeans and other plants.
Before dicamba-resistant crops, approximately 231,000 pounds of the herbicide was spread every year. In 2017, Americans used more than 10 million pounds on cotton and soybean crops, according to the EPA.
Dicamba is popular among farmers because it can kill weeds that have developed resistance to other popular herbicides like glyphosate. In particular, dicamba can kill most palmer amaranth, a difficult to control weed that is already resistant to popular herbicides.
Too many cases and nobody to judge them
State investigators split their time between routine inspections and responding to pesticide use complaints, Pesticide Program Administrator Dawn Wall said. The issue is a lack of dedicated staff to review the pesticide cases, which is what the department is looking for with the two case review positions.
"That's the reason that we need those positions, so that we have folks that, 365 days a year, that's what they're doing," Wall said.
When a producer has crop damage they suspect is from off-target herbicide or pesticide use, they can report it to the department and request an investigation. An investigator will come out to the farm to collect photographs, samples and statements from the farmer. Then they'll talk to applicators in the area and collect records.
It's clear there's been high turnover among the state's investigators, Wall said. Of the eight investigators at the department in 2017, only one is still there. Wall said she couldn't speculate on why people left the department, or say if the spike in workload played a factor.
"There's no denying we have a lot of work here, and that's not going to change," Wall said. "But people leave for a variety of reasons."
It takes two to three months to get a new investigator up to speed, and the department still has two vacant positions, but Wall said high turnover isn't the culprit of the state's backlog. They've still been able to go out and start the investigations, she said, though the volume of complaints was at times more than the staff could handle.
After investigators collect the information, it goes to a case reviewer, who will review all the evidence in the case and determine if anyone violated the instructions on the pesticide or herbicide label.
The department has two people who review cases, and they're both coordinators in the pesticide program who have a lot of other responsibilities, Wall said. Reviewing a case involves carefully going over stacks of documents, and both reviewers look at each case to make sure they're making the right decision, she said. Once they determine if someone was at fault, they send a warning letter or a fine, depending on the severity of the violation and if the person has a history of violations, Wall said.
The department already has the funds for the six new positions, which it expects to cost $628,596, Wall said. Last year, the legislature increased several pesticide registration fees to cover the cost, the department just needs permission from the legislature to add the new positions. The investigators are paid for by a combination of federal grants and the pesticide fees, with no funding coming from the state's general revenue.
Controversial weed-killer has an uncertain future
After complaints peaked at 436 in 2018, there was a sharp drop-off to 141 in 2019. Different people have different explanations for the drop off, and some even disagree about whether there is actually that much less dicamba damage, or if people have just stopped reporting it.
Part of the reason there was less reported damage in 2019 was that flooding kept some producers from planting soybeans or cotton at all, Wall said. The EPA also changed the label instructions for dicamba in 2019 in an attempt to reduce off-target damage.
One change is that producers can now only apply dicamba solutions between one hour after sunrise to two hours before sunset to avoid temperature inversions that can suspend dicamba particles in the air and allow them to spread across neighboring fields.
The EPA also changed the label to add more instruction for cleaning tanks, something MU Extension agronomy specialist for Stoddard County Travis Jones said has led to improvement.
Tank contamination was a major culprit of the damage seen in the first few years dicamba-tolerant seeds were planted, he said. If applicators don't triple-rinse their tanks and use a strong cleaning agent after spraying dicamba, they will cause damage to non-resistant plants if they spray them later, he said.
"If you think about a 1,000 gallon sprayer, you can put one ounce of dicamba formulation in that 1,000 gallons and you will see symptomology on non-tolerant soybeans," Jones said. "So it is highly sensitive."
Mandatory online training courses provided by MU Extension and companies like Bayer walk applicators through the steps they can take to reduce contamination, like limiting the number of surfaces the dicamba solution comes in contact with and cleaning the tank. Private, custom applicators now typically have separate equipment for dicamba so it doesn't contaminate the equipment used on non-resistant plants, Jones said.
Jones said there was definitely less damage from dicamba drift in 2019, in large part because more producers are planting dicamba-resistant soybeans and cotton. Some are shifting because it's a sure way to prevent damage from drift, but dicamba-resistant beans also yield better than traditional varieties, he said.
The drop in complaints has also been attributed to producers just not bothering to complain about their damage. Of the farmers and private pesticide applicators who responded to a University of Missouri Integrated Pest Management survey, 22 percent said they saw symptoms of dicamba injury near them, while just over half of commercial applicators and farm advisors said they did.
The vast majority of those didn't report any damage to the state. Just 5 percent of farmers and private applicators, 17 percent of commercial applicators and a third of advisors said they did. Respondents estimated 70-80 percent of dicamba damage in their area wasn't reported to the department.
Some said they had notified the department in the past, but nothing came of it so they didn't bother again. Some said they didn't want their neighbors to get in trouble, and others said they had caused the damage themselves.
Dicamba has divided agricultural producers. Some see it as a threat to their crops and livelihood, and some see it as an effective tool to fight the threat of weeds. If damage continues, those producers fear they'll lose that tool. It's a fear for Bayer, which merged with Monsanto in 2018.
In February, a federal jury in Cape Girardeau ordered the company to pay $265 million to a southeast Missouri peach producer whose trees were killed by off-target dicamba.
The judgement could be a bad sign for Bayer, which is already facing dozens of other lawsuits over dicamba injury. It's also facing lawsuits alleging its most popular weed-killer, RoundUp, causes cancer, which have already cost the company tens of millions of dollars in judgements.
The company has also been fighting back against efforts to get the EPA to ban spraying dicamba over the top of crops, a fight that will continue this year as the weed-killer's label is up for renewal in December.
Some university researchers have also raised flags about how long dicamba will be effective against weeds that have already developed resistance to other herbicides, particularly palmer amaranth.
The weed is notorious for adapting quickly to new herbicides because they can produce hundreds of thousands of seeds and have both male and female plants, which promotes genetic crossing and speeds up adaption.
Last year, Kansas State researchers confirmed strains of palmer amaranth in that state that were resistant to dicamba and 2,4-D. A University of Tennessee researcher reported palmer amaranth that survived dicamba application last year, but hasn't yet confirmed the weeds are truly resistant.
"There have been a good number of warning signs pointing to the effectiveness of dicamba on Palmer amaranth having a short shelf life," University of Tennessee extension weed specialist Larry Steckel wrote. "Indeed, growers of some of these fields visited this week think the sell-by date has arrived."