EPA is proposing to hold Iowa’s maximum application rate for atrazine unchanged for Iowa corn crops, in its Proposed Interim Decision (PID) on the reregistration of the popular corn herbicide. 

This preliminary decision for atrazine and other triazines (propazine and simazine) are the agency’s “next step” in the periodic, regular reregistration review process that last began in 2013 and is required by the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA). EPA will be taking comment on its proposal until March 2. The maximum application rate for a single preemergence application on non-highly erodible soils in Iowa is 2 pounds per acre, and only 1.6 pounds per acre on highly erodible soils. Actual use rates are usually less.

Atrazine is the most widely used, effective and safe herbicide used on Iowa corn, applied on at least 58 percent of Iowa acres in 2017 to control broadleaf weeds. EPA has time and time again found that atrazine is safe for humans and the environment. It is a key tool in Iowa’s Nutrient Reduction Strategy to reduce phosphorus and nitrogen loss and improve surface water quality, and also in Iowa’s state pest resistance management program. That’s because atrazine is especially effective in today’s high-residue fields, greatly reducing the need for in-season weed control tillage. It has enabled wider adoption of no-till and reduced-till production systems.

As part of this action, EPA is proposing, however, a reduction to the maximum application rate for atrazine used on residential turf, and other updates to the label requirements, including mandatory spray drift control measures. Following the completion of the atrazine reregistration review process, Syngenta – the major registrant of these triazines - will implement a national information and education program geared towards the proper use and handling of atrazine and atrazine-containing products. Topics covered will include: Label education; weed resistance management; vulnerable watersheds; and product knowledge.

The Iowa Farm Bureau Federation is encouraged that the EPA seems to be confirming that atrazine is safe for humans and the environment when used according to label directions and with agronomically recommended application methods. It appears that the EPA has correctly used the best science to reduce the uncertainty and safety factors used in previous risk assessments. The agency also appears to have revised its concerns regarding concentrations in drinking water and impacts to aquatic life and birds.

The IFBF and members of the Triazine Network will be reviewing the PID in more detail and providing comments once published. The Iowa Farm Bureau Federation is a member of the grower network. Once published in the Federal Register, comments can be made at this docket: EPA-HQ-OPP-2013-0266. The EPA is also working with the U.S. Fish and Wildlife Service and the National Marine Fisheries Service to conduct national threatened and endangered species assessments for the triazines in accordance with the Endangered Species Act, which must be completed before the PID is final.

“We appreciate the EPA’s proposal to re-register atrazine,” said Missouri Corn Growers Association CEO and Triazine Network Chair Gary Marshall. “This product is tremendously important to farmers across the country, especially for weed control in conservation practices. From citrus to sorghum and corn to Christmas trees, farmers rely on the agency’s use of credible science to regulate the products that allow us to safely grow more with less for a hungry global population.”