In August 2024 the US Environmental Protection Agency (EPA) finalized their Herbicide Strategy to ensure that all newly registered and re-registered herbicides are in compliance with the Endangered Species Act.  This strategy ensures that herbicides can be used without adversely affecting threatened and endangered species or the habitat that they rely on for survival.  While the science and process to develop the strategy was rather complex, the goal of this article is to simplify the outcome into a few required steps before using herbicides.  It’s important to note that compliance with the Herbicide Strategy requirements is mandatory and not voluntary.

Where can I find the Endangered Species Act herbicide use requirements?

The details of what’s required to reduce the risk of herbicide drift or runoff/erosion around threatened and endangered species are found in two locations, both of which need to be visited prior to herbicide use: the herbicide label itself and the Bulletins Live! Two website.

The herbicide label will include requirements for reducing spray drift and runoff/erosion risks.  For spray drift, first a maximum buffer distance is established based on application characteristics such as droplet size and aerial vs ground boom delivery. That buffer distance can then be reduced by adopting mitigation measures from options listed on the product label or by getting credit for those already implemented (like wind breaks). The list of drift mitigation strategies is specific, including aspects such as droplet size, wind speed, hooded sprayers and relative humidity.

For runoff and erosion, first a point level for the amount of needed mitigation is established based on the risk for each herbicide. The risk level for each herbicide ranges from 0 (low risk) to 9 (high risk). Applicators and farmers can then select from a menu of mitigation strategies to meet that necessary point level. For example, if the label indicates that the herbicide requires 6 mitigation points, then the total points for the adopted mitigation strategies needs to be 6 or greater.  Some strategies are worth 1 point (lower likelihood of success) up to 3 points (high likelihood for success). Examples of mitigation strategies include cover crops, terrace farming, vegetated ditches, and grass waterways.  The mitigation menu is quite extensive, and details can be found at: https://www.epa.gov/pesticides/mitigation-menu.

Additionally, the geographic location itself may be assigned mitigation points based on topography, soil type and precipitation, among other factors.  In Wisconsin, most counties are assigned 2 or 3 runoff/erosion mitigation points.  The listings by county can be found at: https://www.epa.gov/system/files/documents/2024-10/county-mitigation-relief-points-runoff-vulnerability.pdf.

Some pesticides may also include Pesticide Use Limitation Areas (PULAs) where there will be additional mitigation requirements for specific field locations listed in the Bulletins Live! Two online resource (https://www.epa.gov/endangered-species/bulletins-live-two-view-bulletins).  The Bulletins Live! Two system allows the user to select the field location on a map, select the month in which they anticipate applying the pesticide and enter the pesticide EPA registration number.  Alternatively, if the field location and application months are selected, but the EPA registration number entry left blank, all pesticide use limitations for that field and application month will be shown.  The full details of the use limitations are then available in a printable bulletin specific to the field location.  Please consider watching the EPA’s webinar on Bulletins Live! Two for a more in-depth tutorial: https://www.epa.gov/endangered-species/materials-november-2023-bulletins-live-two-webinar.

If that understandably still seems quite complex, try this simple recipe to learn how to comply:

1. Check the pesticide label for Endangered Species Act language:
   1. What is the spray drift buffer distance requirement, and what strategies are listed that can be used to reduce the buffer size?
   1. How many runoff/erosion mitigation points are required to be able to use the pesticide?
2. Visit the online EPA runoff/erosion mitigation menu to see what the options are to get enough cumulative points to equal or exceed the mitigation point requirement listed on the pesticide label.  Be sure to check the county mitigation map also for points associated with the field location.
3. Check the Bulletins Live! Two system for any Pesticide Use Limitation Areas (PULAs) specific to the field location, application month and pesticide product.

All new herbicide labels will include Endangered Species Act language.  The recent Liberty^Ò Ultra herbicide label was the first to include new Endangered Species Act requirements.  Others will follow as new products are registered and existing products go through the regular re-evaluation process that occurs at least every 15 years.  A very similar Insecticide Strategy was also released in late April 2025 and will be followed by consideration of a Draft Fungicide Strategy.  It’s expected that there will be much commonality among these three strategies.  And, this continues to be an evolving situation, so be sure to check the pesticide labels and the Bulletins Live! Two system frequently.  If you’d like to receive information on changes to the strategies, mitigation options, Bulletins Live! Two and other related news, consider signing up for the EPA’s online news notifications: https://www.epa.gov/newsroom/sign-news-epa.

This article was posted in Other News and Resources and tagged EPA, herbicide, Jed Colquhoun.