A celery field in the Salinas Valley is harvested. Credit: Ag Alert file photo
September 8, 2024 - By Christine Souza - Reacting to the emergency suspension of an herbicide used to control weeds in vegetable crops, farmers and agricultural representatives are asking for more guidance as the sector considers effective alternatives, disposal of existing inventory and potential liability issues.
Unlike typical pesticide cancellations that allow for a phase-out period, the Aug. 6 action by the U.S. Environmental Protection Agency immediately restricts the use, sale, distribution and transportation of Dacthal, the trade name for dimethyl tetrachloroterephthalate, or DCPA.
This is the first time in 40 years the EPA has used its emergency authority under the Federal Insecticide, Fungicide and Rodenticide Act to suspend use of a federally registered pesticide due to concerns about potential health risks.
San Luis Obispo vegetable grower Tom Ikeda reacted to the EPA decision to ban the herbicide, which he said is used by growers as a preplant treatment in crops including broccoli, cabbage, cauliflower and onions. “Basically, the agency said, ‘Stop using it,”’ he said.
“In talking to people in my area, they want guidance on what to do with stocks of this material,” Ikeda said. “We’re waiting to see what’s going to come of it because there’s probably tons of product out there that people are wanting to know how to dispose of.”
Since the EPA issued the emergency suspension early last month, it released a frequently-asked-questions document with more information on the path forward. It included a clarification that growers may transport existing inventory of Dacthal to return stocks of the herbicide to the retailer or the registrant.
“The EPA has finally provided needed information for growers who have used DCPA in the past,” said Norm Groot, executive director of the Monterey County Farm Bureau. “Hopefully, a solution can be worked out soon to remove existing stock from farms and return to the manufacturer for refunds and proper disposal.”
A use assessment conducted by the EPA last spring found that DCPA applications were made primarily to broccoli, cabbage, cauliflower and dry onions, and mostly in California.
In California, 192,900 pounds and 188,200 pounds of DCPA were applied in 2021 and 2022, respectively, according to a report prepared for the state by the Department of Agricultural and Resource Economics at the University of California, Davis.
As a top vegetable producer, Monterey County led California counties in applications of 79,000 pounds of DCPA in 2022, with most of the herbicide treatment applied prior to planting broccoli.
“The biggest concern we’re seeing here in Monterey County is for our onions and our broccoli crops, and how those are going to be managed going into the future to control weeds,” Groot said.
With the use of Dacthal suspended, there are only a few alternatives available to growers, Groot said, noting that these materials require more frequent applications and may involve harsher chemicals.
Soon after the EPA issued the emergency order to remove DCPA from the market, the California Department of Pesticide Regulation announced it is working to support the availability of alternative pesticides to control weeds in affected crops.
DPR said it will prioritize applications for full registration of alternative products. In addition, it is providing assistance to stakeholders to make alternatives available through an emergency exemption for special local needs under FIRA.
The Dacthal ban has introduced liability concerns for growers. Groot said some buyers and shippers are asking growers for assurances that the herbicide was not used on crops purchased, which could lead to the rejection of products even if the herbicide was legally applied before the ban.The situation creates potential contractual disputes and financial losses for farmers, he said.
The EPA and others noted the suspension of Dacthal is not a food safety issue. EPA said it has not identified risks from consuming foods with residues due to use of DCPA on crops as allowed by registered labels.
The California Agricultural Commissioners and Sealers Association, which represents agricultural commissioners in every county, also said the ban is not related to food safety concerns.
“(Dacthal) is typically applied at the same time the crop is being planted and is not used on vegetable plants during the growing cycle. As such, DCPA is not considered a food safety concern for consumers,” the association said.
Any applications of DCPA on commodities listed on the product label prior to the suspension by the EPA were legal and subject to strict residue tolerances to ensure the safety of consumers, the association added.
In response to the EPA’s emergency suspension of the herbicide, the association has notified California farmers that they must immediately discontinue use of DCPA products, and that agricultural commissioners will enforce the ban to ensure compliance. This includes physical inspections of farming businesses to make sure pesticide regulations are followed.
American Vanguard Corp., the registrant and sole manufacturer of DCPA, voluntarily stopped sales of the affected products in April. The company submitted cancellation requests to the EPA for federal registrations of the products due to the agency’s assessment that DCPA is harmful, particularly to pregnant women and developing fetuses.
In a statement, the company said it “continues to question EPA’s conclusions in support of the suspension,” adding that the EPA decision is based on test results of one study provided by the company that showed an effect on fetal rodents at certain dose levels. The observed effect was extrapolated to indicate a potential effect upon humans, the company added.
American Vanguard is working with state and federal authorities on a product return program that includes tracking of the remaining stock of DCPA products and removal of the banned herbicide from distribution channels.
(Christine Souza is an assistant editor of Ag Alert. She may be contacted at csouza@cfbf.com.)
