The Endangered Species Act (ESA) has existed since 1973 and was implemented to ensure that any actions taken by a government agency did not jeopardize any species that are federally listed as threatened or endangered. So, why are we now talking about this law in 2025, nearly fifty years after its original passing? The EPA (Environmental Protection Agency) as a federal agency is responsible for regulating pesticide use, which can affect animals and plants or their habitats. Due to this the EPA has a responsibility to consult with the U.S. Fish and wildlife Service and/or the National Marine Fisheries Service to ensure its actions (registration of pesticides) do not jeopardize any threatened or endangered species or their habitats. As one might imagine, this is a complex process and the EPA had not been fulling completing the consultation process for past pesticide registrations. This has left many pesticides vulnerable to lawsuits that have resulted in a few pesticides being pulled from the market. In response, the EPA has spent the past half decade developing strategies to ensure all future pesticide registrations are more secure and are complying with ESA. The first strategy to be implemented in August 2024 was the “Herbicide Strategy to Reduce Exposure of Federally Listed Endangered and Threatened Species and Designated Critical Habitats from the Use of Conventional Agricultural Herbicides,” more commonly referred to as the “Herbicide Strategy.”

The following list of questions and answers is intended to assist Kentucky growers and applicators in understanding how the strategy will affect herbicide applications in the future. While the strategy looks very complicated on its face, our goal here is to help alleviate some of the complications and show that Kentucky growers can meet the new requirements with minimal, or in many cases no changes to their current practices. If you would like to see the full 79 page strategy and its many appendix’s and supporting documents, you can find them here: https://www.epa.gov/endangered-species/strategy-protect-endangered-species-herbicides. 

How will this affect the herbicides applications made to your field?

All future herbicide labels receiving a new registration or a registration review (which occurs every 15 years) will likely have the following mitigations added to the label:

• Spray Drift Mitigations
• Runoff/erosion Mitigations
• Requirements to check the EPA’s Bulletins Live! Two website for further restrictions specific to the herbicide being applied and location of the application

When will the new ESA requirements be implemented?

As is alluded to in the above bullet point, this will not be an instant flip of the switch (no ESA mitigations one day and full mitigations the next). Rather ESA mitigations and restrictions will be added to all new herbicide registrations as they occur. They will be added to all existing herbicide labels when those products go through the registration review process that must occur every 15 years. In essence, the mitigations will be rolled out on a label-by-label basis over the next 15 years. The first herbicide to receive the ESA requirements on its label is the newly registered Liberty Ultra. We will use Liberty Ultra as our example in the questions below.

What will the spray drift mitigations look like?

Spray drift mitigations will appear as required downwind buffer distances that must be implemented during the application of that herbicide. The distance of these downwind buffers will differ for each product based on the EPA determination of the potential impact that product may have on endangered or threatened species at the population level. Downwind buffer distances for ground applications will range from 0ft to a maximum of 230 ft. The Liberty Ultra label has a downwind buffer distance of 10 feet for ground applications.

These downwind buffers, especially those that occur at the 230ft level, look very arduous, but they do not have to occur completely within the field that is receiving the application. The following areas can be included in the downwind buffer distance if they occur immediately adjacent to the field receiving the application. (The area descriptions are directly from the EPA Herbicide Strategy)

a) Agricultural fields, including untreated portions of the treated field;
b) Roads, paved or gravel surfaces, mowed grassy areas adjacent to field, and areas of bare ground from recent plowing or grading that are contiguous with the treated area;
c) Buildings and their perimeters, silos, or other man-made structures with walls and/or roof;
d) Areas maintained as a mitigation measure for runoff/erosion or drift control, such as vegetative filter strips (VFS), field borders, hedgerows, Conservation Reserve Program lands (CRP)1, and other mitigation measures identified by EPA on the mitigation menu;
e) Managed wetlands including constructed wetlands on the farm; and
f) On-farm contained irrigation water resources that are not connected to adjacent water bodies, including on-farm irrigation canals and ditches, water conveyances, managed irrigation/runoff retention basins, and tailwater collection ponds.

Lastly, if these areas are not immediately adjacent to the field in the downwind direction, there are additional measures that can be implemented to reduce the downwind buffer distance. A complete list of potential mitigation measures can be found in Table 8 (Page 37) in the Herbicide Strategy. These mitigations include simple mitigations, some that you are likely already implementing, such as the use of a coarse droplet can reduce the buffer distance by 65 to 75% depending on boom height. Additionally, applying when relative humidity is above 60%, which occurs nearly every day in a KY summer, allows for an additional 10% reduction in buffer distance. These mitigation percentages are cumulative, so in essence, if you can find mitigations that add up to 100%, you can completely eliminate the downwind buffer for that application.

In the case of Liberty Ultra, the downwind buffer of 10ft for ground applications is very manageable and is an encouraging signal that downwind buffers on future labels are likely to be reasonable and manageable.

What will the runoff/erosion mitigations look like?

Runoff/erosion mitigations will appear on labels as runoff mitigation points that are required for application of the given product. Like spray drift mitigations, the runoff mitigation points needed for a product will be based on the EPA’s determination of the likelihood of the product to move in surface runoff or move with soil in an erosion event. The number of runoff/erosion mitigations points on a label will range from 0 to a maximum of 9 points. The Liberty Ultra label requires 3 runoff mitigation points.

Runoff mitigation points can be acquired through a number of practices, many of which Kentucky farmers are already implementing on their fields. A full list of mitigations and the points given for each can be found here: https://www.epa.gov/pesticides/mitigation-menu or in a PDF version:
https://www.epa.gov/system/files/documents/2024-10/mitigation-menu-pdf-version.pdf

While this list is extensive and seems complicated, remember that these mitigations are in place to allow for any applicator in any crop across the United States to be able to reasonably meet the mitigation points needed to apply herbicides. Thus, complicated = more options, and more options is to the benefit of famers and applicators.

Here are a few examples of in-field and field-adjacent mitigations (not a complete list of mitigations) and their point values that are relevant to the state of Kentucky and are being implemented already in many fields:

Additionally, you can get mitigation points for the following:

• If you are tracking mitigation points you receive 1 point
• If you are working with a specialist to implement measures to reduce erosion in your field or are implementing a conservation program on your field you can achieve 1 to 2 points.
• If you implementing mitigation measures from both the in-field and field-adjacent menus you will receive 1 additional point

Lastly, many Kentucky counties receive mitigation relief points based on their determined vulnerability to soil erosion/runoff. See the bullet below for a map of those counties in KY.

If you are not able to achieve the points required with the above in-field and field-adjacent mitigations, there are additional steps that you can take. Such as if you are applying at a rate that is a reduction of the annual maximum or reducing the proportion of the field receiving the application can achieve additional points. Although, as you will see below, I believe most Kentucky farmers will be able to achieve 6 to 9 points without making any changes to their current practices.

As an example, I did a runoff/erosion mitigation calculation for a field at the UKREC:

In this example I would be able to apply Liberty Ultra (only requires 3 mitigation points) as well as any herbicide in the future that requires the maximum 9 mitigation points.

While currently we only have Liberty Ultra with the required runoff/erosion mitigations, a farmer can conduct a calculation on each of their fields now and see if they can reach the maximum 9 points with the practices they are already implementing on their field. Again, I believe that most fields in Kentucky will be able to achieve 6 to 9 mitigation points without implementing any changes to current practices.

Lastly, the EPA has released a handy mitigation calculator that you can use to quickly make your mitigation calculations for each field on your farm.

How many runoff/erosion runoff relief points do Kentucky Counties receive?

A complete list of counties in the US can be found here: https://www.epa.gov/system/files/documents/2024-10/county-mitigation-relief-points-runoff-vulnerability.pdf 

Additionally, here is a map of Kentucky with the assigned runoff/erosion mitigation relief points:

Are there any scenarios in which Runoff/Erosion mitigations are NOT required?

Yes, there are scenarios when an applicator does not need to calculate or implement runoff/erosion mitigation measures. You can find a list of these scenarios on the EPA mitigation menu website. I am choosing not to list these in their completeness in this article as most do not apply to Kentucky corn, soybean, and wheat applications/fields. I would still encourage you though to check the EPA mitigation website to make sure these scenarios do not apply to you. Additionally, the mitigation calculator builds in these scenarios and will let you know you can stop the calculation process.

What is Bulletins Live! Two? And should I be using it?

Yes, you should be actively using Bulletins Live! Two. This website indicates if you need to implement any further restrictions, beyond those already on the label, on your particular field for a pesticide application to protect endangered species. The website allows you to zoom in on a map of your field and check to see if there are any PULA’s (Pesticide Use Limitation Area) encompassing the field you plan to apply a pesticide to, if so you must follow the additional restrictions listed on the bulletin that the website will provide you. If your field is not within a PULA you can proceed with your application without any further restrictions beyond those on the label. You can check Bulletins Live! Two up to six months prior to your application, thus you can go ahead and check all of your fields now for applications you will make through September of 2025.

Why does compliance matter?

The steps being taken by the EPA and the compliance of applicators ensures that famers and applicators will continue to have reliable access to the herbicides needed to protect crops from weed interference, while also continuing to protect valuable endangered and threatened species.

Citation: Legleiter T., 2025. Endangered Species Act – How will it affect you in the near future? Kentucky Field Crops News, Vol 1, Issue 3. University of Kentucky, March 14, 2025.

Dr. Travis Legleiter, UK Extension Weed Specialist
(859) 562-1323 
travis.legleiter@uky.edu