Herbicide use is likely to increase in complexity in the coming years, due in part to the EPA’s Herbicide Strategy that was finalized and published in August 2024, among other anticipated changes. One thing that has not changed is that the “label is the law”, and off-label herbicide applications come with potential liability and legal implications, along with potential damage to crops and surrounding areas. In most instances, application cutoff dates are imposed due to increased risk of off-target movement or concerns about herbicide residues in the crop when applied after a certain growth stage. Seed suppliers often send letters this time of year reminding growers that they are also legally bound by the terms of the Technology Use Agreement (“TUA”) entered into with the seed supplier. A TUA contains herbicide application restrictions for the seed variety. Growers should familiarize themselves with the TUAs for their seed products and be aware that a TUA also grants the company rights of access to inspect crops and ensure compliance with the herbicide application provisions.
Here are a couple of reminders as we head into the 2025 growing season regarding the application of herbicides POST in the available traited soybean systems.
Enlist
- Where 2,4-D is applied preplant or preemergence for burndown ahead of planting Enlist soybeans, the application of products that are not labeled for use in the Enlist system must adhere to the labeled plant back interval for the product used.
- At present, the only 2,4-D products that are labeled for immediate plant back and over-the-top (OTT) application in the Enlist soybean system are Enlist One (2,4-D choline) and Enlist Duo (2,4-D choline + glyphosate).
- Growers across the state have been receiving “technology use agreement” letters reminding growers of this, and the fact that it is the growers’ responsibility to ensure that only these products are being applied, regardless of who is making the application. In these letters, potential steps were listed in response to not following these parameters. These steps included: investigating reports of misuse, in-person audits during the 2025 growing season, revoking the grower’s access to the trait technology, and reporting violations to the EPA.
Xtend
- In February 2024, the EPA vacated registration for the three dicamba products labeled for OTT applications in soybean (Xtendimax, Bayer; Engenia, BASF; and Tavium, Syngenta).
- Shortly after, the EPA issued an existing stocks order for use of these products for the 2024 growing season. The last date for application of these products in Ohio was June 30th, 2024.
- At present, there are no options for OTT application of dicamba for growers using Xtend or XtendFlex soybeans for the 2025 growing season. Postemergence control of broadleaf weeds is limited to glyphosate and glufosinate in the XtendFlex system. PPO inhibitors (fomesafen, etc.) can be used POST in any soybean system.
Liberty
- Soybean yields generally benefit from earlier planting dates, and growers in the region have been planting earlier than the historical norm for the state. Depending on the date of planting, this can have implications for time to soybean emergence and maturity and in some cases can lead to earlier soybean flowering dates.
- As a reminder, glufosinate can be applied to glufosinate-resistant soybeans from emergence up to soybean bloom (R1).
Source : osu.edu