Without the option of dicamba, more growers will be relying on 2,4-D and glufosinate for POST herbicide applications in the respective traited soybean systems. A previous C.O.R.N. article, “Considerations for Soybean Trait Programs in 2025” covers reminders for use of these products in 2025, and especially for the Enlist system.
There are further considerations for the use of glufosinate this growing season in terms of product options and label requirements. The registration for a new BASF product, a reformulation of Liberty (glufosinate) called Liberty Ultra, was approved last October. Standard glufosinate products are a blend of the inactive D-isomer molecules and active L-isomer molecules. This means a portion of the product is in an inactive form. Liberty Ultra is a reformulated product wherein the D-isomer has been transformed to L-isomer. This means a greater portion of the product is in an active form, allowing for lower use rates of Liberty Ultra than other glufosinate products. It is expected that these reformulations will replace the standard glufosinate products over time.
Liberty Ultra is also the first herbicide label registered under the new guidelines from the EPA to improve compliance with the Endangered Species Act (ESA). Following these guidelines, including diligent record keeping, ensure that growers are better protected in the event of off-target movement.
These label guidelines include:
- Label Section 12. Endangered and Threatened Species Protection Requirements: instructions to download Endangered Species Protection Bulletins from Bulletins Live! Two (https://www.epa.gov/pesticides/bulletins) six months prior to or on the day of application
- Shows application requirements that are location specific and not listed on the herbicide label
- Application requirements listed on the label that are to be followed anywhere Liberty Ultra is used (Label sections 9, 10 and 11):
- Wind speed and direction must be measured on location
- Sustained wind speed must be between 3 and 15 MPH, measured at the release height or higher, in an area free from obstructions
- Mandatory 10 ft downwind spray buffer for ground application, reduced to 0 ft if:
- Using a drift reducing adjuvant
- Using a hooded sprayer
- A windbreak or shelterbelt is present
- Three runoff mitigation points required
- Check the mitigation options at https://www.epa.gov/pesticides/mitigation-menu
- Across Ohio, most counties already have 2-3 mitigation points based on runoff vulnerability https://www.epa.gov/system/files/documents/2024-10/county-mitigation-relief-points-runoff-vulnerability.pdf
- Many farms across the state already implement some of the other mitigation options in their operation, including conservation tillage (qualifies for 3 points) or cover cropping (qualifies for 1-3 points)
- Check the mitigation options at https://www.epa.gov/pesticides/mitigation-menu
Another important application consideration that relates to the use of Liberty Ultra is the adjuvant requirements per the approved Enlist tank-mix list. According to this list, when Enlist One is applied with Liberty Ultra, this combination requires an additional MSO, HSMSO (High Surfactant MSO) or HSCOC (High Surfactant COC) tank-mix partner (https://www.enlist.com/en/herbicides/approved-tank-mix/enlist-one-tank-mix-products.html).
Last week’s episode of the War Against Weeds podcast featured guests Liam Vincent (BASF) and Lynn Justenseen (UPL) and covered this topic, including information on reformulated glufosinate products, the ESA compliant labels and associated use requirements. Listen to the episode here https://waragainstweeds.libsyn.com/s9-e14-liberty-ultra-label-esa or anywhere podcasts are available. Resources with more information about the Endangered Species Act (ESA), the EPA’s Herbicide Strategy and links to associated webpages can be found here: https://u.osu.edu/osuweeds/multimedia/endangered-species-act/.