A rule banning almost all uses of chlorpyrifos, a commonly pesticide used in conifer production and other crops, has now taken effect across the state, effective December 31, 2023, Oregon Public Broadcasting reported .
The chemical has been associated with neurological damage to humans, prompting states and the U.S. Environmental Protection Agency to consider stricter regulation or a full ban.
Oregon’s rule was announced three years ago and was to be phased in over three years. Applications on food crops were the first to be disallowed. The last remaining exceptions to the ban are commercial pre-plant seed treatments, cattle ear tags, and use of the granular form to control soil-borne pests.
“The department has not proposed a complete ban because these limited uses pose a lower risk to applicators, workers, bystanders, and the environment,” Andrea Cantu-Schomus, a spokesperson for ODA, said in a written statement, as reported by OPB. “In addition, there are currently few insecticides which control soil-dwelling pests as effectively as chlorpyrifos.”
Environmental groups would like to see the remaining exceptions go away, as well, but the state has not agreed.
The pesticide, sometimes known by the trade name Lorsban®, has been commonly used for aphid control in Christmas tree production, and other conifer production, according to a Growing Knowledge article by Extension expert Chal Landgren and other Oregon State University researchers in the March 2019 issue of Digger magazine.
The aphids don’t kill the trees but can make them unsellable. Growers would apply the pesticide in liquid form at 32 ounces per acre, the article stated. The researchers were aware the pesticide has long been under scrutiny, so they did research evaluating various alternatives.
“It’s not particularly pleasant to be around. But it works on aphids,” Landgren told OPB in 2018. “Nobody wants to wear respirators and Tyvek suits out spraying. That’s a concern for growers, applicators, everybody.”
Meanwhile, the EPA has revoked all tolerances for its use on food products, but that action is presently tied up in court. A timeline of EPA regulation of the pesticide can be found here.
