BioCycle August 2010, Vol. 51, No. 8, p. 32
Crop damage in Washington State, likely associated with manure and compost tainted with aminopyralid, is reminiscent of the presence of clopyralid in compost in the early 2000s.
Dan Sullivan

A nonprofit that operates several organic farms and agriculture-oriented social-service programs in Washington state surrendered its organic certification in an act of protest in July, following severe crop damage linked to herbicide-tainted manure and compost used on those farms. States a press release issued by Growing Washington to explain its motives:
“This decision of protest is made with high hopes that both the manufacturers of potent, persistent, widely disseminated herbicides and the agencies tasked with regulating and permitting their use can work together to protect the welfare of the general public and also the welfare of farmers who are experiencing incredible losses that WSDA- [Washington State Department of Agriculture] administered soil and tissue tests trace back to these persistent herbicides.”
The herbicide that Growing Washington Director Clayton Burrows and others have linked to withering crops is aminopyralid, manufactured and marketed in the U.S. by Dow AgroSciences under the brand name “Milestone.” Burrows estimates crop damage will cost Alm Hill Gardens, one of the farms managed by Growing Washington, into the hundreds of thousands of dollars. Garden centers in the Whatcom County area (in northwest Washington near the Canadian border) – and the gardeners who purchase soil blends made with regionally sourced manure and compost – have also been affected.
“Dow sent a lot of people up there and the agency [WSDA] did the same,” Burrows says. “I think they’re worried. People are calling and saying ‘I have that problem, too.’ We’ve got home gardeners saying ‘I wondered what was wrong with my stuff.'”
While acknowledging an existing problem, officials at WSDA – which both regulates the use and application of pesticides and oversees the state’s organic program as an agent of the U.S. Department of Agriculture – says the jury is still out on the cause. “Our agency is not ready to confirm that the only pesticide in question is aminopyralid or some other pesticide,” says WSDA Public Information Officer Mike Louisell. “It’s inconclusive at this point which pesticides are involved. It could be a combination of chemicals causing problems in compost.”
Milestone is used by area dairy farmers to control certain invasive weeds in hayfields. The product’s label states: “Do not spread manure from animals that have grazed or consumed forage or eaten hay from treated areas within the previous 3 days [of application] on land used for growing susceptible broadleaf crops.” The label goes on to explain that such manures may only be safely applied to pasture grasses, grass grown for seed and wheat. The label also warns: “Do not plant a broadleaf crop in fields treated in the previous year with manure from animals that have grazed forage or eaten hay harvested from aminopyralid-treated areas until an adequately sensitive field bioassay is conducted to determine that the aminopyralid concentration in the soil is at a level that is not injurious to the crop to be planted.”

DOW RESPONSE
Reiterating that aminopyralid has not yet been formally tied to the Whatcom County damage – at press time WSDA test results were expected to be released any day – Dow AgroSciences spokesman Gary Hamlin says isolated crop damage that had been conclusively linked to the herbicide elsewhere in the U.S. and abroad was due to users not following proper “stewardship protocols” outlined on the label. North Carolina farmers and gardeners reported aminopyralid-related crop damage in 2008, the same year Dow AgroSciences voluntarily suspended sale of the herbicide in the United Kingdom following damage to susceptible crops in backyard and community gardens. It was reintroduced in certain parts of the UK in April of this year under stricter manure-management controls. Additional problems emerging there this summer were attributed by Dow to manure stockpiled from a previous growing season before the label restrictions had changed.
“This is disappointing and upsetting for those affected,” Dow AgroSciences UK division’s principal biologist Andy Bailey stated in a June 17, 2010 press release. “Although of small comfort, we would reassure anyone affected that this manure has not come from use this season under the new controls. It is a reflection of manure generated from past treatment and kept in heaps for more than a year.” The press release goes on to explain that “the new restriction in aminopyralid use will mean any manure returns immediately to pasture where it will cause no harm and cannot leave the farm.”
Dow’s Hamlin declined specific comment as to what compensation affected farmers might expect if aminopyralid is ruled to be the culprit in Whatcom County. “Clearly, if our product caused damage to your produce we would like to talk to you about that for a variety of reasons,” he says. Hamlin says the company is working with agencies that regulate pesticides to see if additional restrictions and protocols might be warranted. “We’re meeting with regulators and growers that have claimed herbicide damage to crops. I understand it’s a situation where stewardship has broken down, and we need to trace to source.”
Aminopyralid is used extensively across the United States without incident, Hamlin adds. “There are two ways of looking at this through the same telescope. The local situation is one instance, and it’s unacceptable. On the other hand, overall stewardship has largely been a success.” As for the problems in the UK – where Dow markets the herbicide under the product names “Forefront,” “Pharaoh,” and “Banish” – he says: “We needed to change the labeling of the product in recognition of the unique nature of British agriculture. On the dairy farms, a lot of manure accumulates that has to go somewhere.”

CLOPYRALID CONNECTION
This isn’t the first time a persistent Dow chemical has spelled problems for Washington state agriculture and farmers who use compost. “Dow’s official stance is that the label is clearly marked,” says Burrows. “It was the same issue with [the herbicide] clopyralid back in 2000, 2001, 2002 and 2003. People using these products had it on their lawns, and the city of Seattle was taking it in to its yard waste recycling.” Clopyralid, also used by farmers to control Canada thistle, was ultimately banned for use on residential lawns.
“This is not a new issue, it’s just like replaying an old issue,” says Burrows. “In that case I think if an agency is going to control the word ‘organic’ and take money from organic farmers to support an organic program, that this is self-defeating and contradictory.” WSDA’s Louisell says the various divisions are working together to address the situation: “The Washington State Department of Agriculture is approaching this problem from at least three programs: our Pesticide Management Division’s Compliance Program that took the complaint from a small number of farmers and gardeners in Whatcom County; our Organic Food Program that licenses organic farmers and the materials that they use; and our Small Farm & Direct Marketing Program that assists small farm operators. These programs are well-run and respected by the agricultural community in general and want to be helpful in contributing to solutions.”
Cedar Grove Composting chief sustainability officer Jerry Bartlett recalls the clopyralid issue only too well and says its incumbent on composters to know they are providing products free from chemicals that could harm crops. “Cedar Grove is lucky, in one way, in that we don’t take manure or bedding into any of our composting systems,” he says. The commercial composting facility, located two counties south of where the new trouble is unfolding, does incorporate some already composted livestock manure into certain blends, Bartlett adds, but the manure composter tests for aminopyralid and sources the manure from confined animal feeding operations.
“This issue isn’t like clopyralid, which was used in an urban environment,” he explains. “Making sure compost is pesticide free or at least active-ingredient free – that is the composter’s responsibility. That’s why we spent so much time trying to ban clopyralid. I think what’s happening is that a lot of folks are buying manure that either isn’t registered or isn’t composted – that is a different product than when you’re dealing with a permitted facility.”
Bartlett calls the banning of clopyralid for urban application (with the exception of golf courses, which must now compost on-site) a success story that demonstrates how government, industry and concerned citizens and farmers can work together to solve a difficult problem. New restrictions on the herbicide still allow for spot application of clopyralid in low concentrations to control Canada thistle in hayfields, he says. “I can understand why they didn’t want to completely ban it. Canada thistle is deadly to horses. That program has been incredibly successful. It just disappeared in feedstocks. We did bioassay tests for years after the ban went into effect and there was no trace of clopyralid.” WSDA’s Louisell says he hopes for a similar resolution with aminopyralid. “We do have people alleging problems who have been applying straight manure that has not been worked at all,” he says.
Colleen Burrows, Washington State University Whatcom County Extension Integrated Pest Management Coordinator, suggests certain agricultural chemicals simply may not be a good fit with respect to certain agricultural systems. “Our county is different from other dairy counties in that farmers have less land,” she says. “They top cut green hay and feed it to their cows, and they don’t have enough land to apply all their dairy manure back onto their grasslands. A lot of it goes to haulers who service sustainable agriculture enterprises, or to composters, and it ends up in three-way or five-way mixes for home gardeners.”
Dairy farmers do not routinely perform the pesticide applications themselves, Burrows says, but rather hire the task out to commercial vendors. “The dairy farmer may not have even known the implications of that particular pesticide,” she explains, adding that her office is not concerned with placing blame but rather in resolving the issue. “Every day I hear of more cases from small farms and home gardeners,” continues Burrows, whose office has had discussions with all parties involved with the issue. The application of aminopyralid might be more suited to areas where there was plenty of land for recycling of nutrients, she says. “I question whether aminopyralid should have been used in our system at all.”

Photo courtesy of Washington State University ExtensionPhoto courtesy of Washington State University Extension