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Task force to look at herbicide issues

Chemicals kill weeds as well as desired crops
Terry Fitzgerald talks about her tomato plants suffering from curly leaves in her greenhouse outside of her home southeast of Bayfield on Wednesday.

La Plata County commissioners on Wednesday created a task force to find ways to spare backyard gardeners and commercial farm and ranch operations from herbicides that wipe out desired crops along with invasive weeds.

Commissioners were reacting to a petition with 39 signatures that asked the county to look into widespread loss of broadleaf crops such as tomatoes, potatoes, peppers, spinach and legumes to herbicides.

Insects and viruses have been ruled out as guilty parties. Instead, three classifications of herbicides are believed to raise havoc.

The aminopyralid chemicals are widely used in pastures to control broadleaf invasives such as Canada thistle and species of knapweed that reduce forage crops and degrade rangeland but spare grass. Unfortunately, the herbicides don’t distinguish among broadleafs.

Trouble begins when horses and cattle feed on grass or hay sprayed with the herbicides. The chemicals, which take years to decompose, live on, likely at near full strength, in livestock manure. The final step occurs when manure and hay, combined to form compost, are purchased by home gardeners and commercial growers.

The herbicides begin to attack the broadleaf vegetables.

Darrin Parmenter, horticulturist with Colorado State University Cooperative Extension in Durango, and Rod Cook, the La Plata County weed manager, provided technical information Wednesday.

Parmenter said he receives probably 200 inquiries a year about herbicide problems.

The immediate focus of the task force will be education because public knowledge about the herbicides is limited.

Unless the use of a chemical is restricted, it’s buyer beware. Many herbicide users learn the hard way, seeing crops wither or not even germinate, participants at the organizational meeting Wednesday learned.

Herbicide manufacturers put warnings about the application of their product on container labels, but many herbicide users don’t bother to read the information.

Cook said that a label on containers of the widely used herbicide Milestone spell out restrictions. Hay from areas treated with Milestone can’t be sold off the farm, even for foreign export, for 18 months after harvest, Cook said.

No license is required to buy Milestone, but restrictions on distribution of hay is governed by federal regulation through the Environmental Protection Agency, Cook said.

Among those mentioned at the Wednesday meeting who need to learn about herbicide danger and measures to mitigate its effects are applicators, home gardeners, commercial growers, hay producers, gas- and oil-well owners, stable owners and suppliers of top soil.

One suggestion was to build a database with information on where hay is grown and distributed, on who sells manure and on the location of herbicide hot spots.

Unless the state Department of Agriculture requires herbicides to be licensed, end users must learn to protect themselves, Parmenter said.

Cook said invasives can’t be uprooted. The root of Canada thistle goes down 15 feet; Russian knapweed roots reach down 20 feet; and Leafy spurge roots are up to 30 feet long.

Linley Dixon, with Adobe House Farm, said she can’t raise tomatoes in a $10,000 greenhouse because the beds are one-third compost that she acquired years ago.

“I’m growing other things – and waiting,” Dixon said.

Aminopyralids were banned in Europe from 2008 to 2011, Dixon said. Now, they can be sold only by special permit, she said.

“There is an education gap,” Dixon said. “Open communication is not happening.”

daler@durangoherald.com



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