There has been much uncertainty regarding the use of dicamba for the 2024 growing season and beyond as a result of the vacated dicamba registration in February and the EPA’s existing stocks order for dicamba use in 2024 that soon followed. The EPA’s order allowed for existing stocks of dicamba products (Engenia, Tavium, and XtendiMax) purchased for use in dicamba-tolerant (DT) soybeans to be sold and distributed through May and to be applied through June. The future of dicamba applications over-the-top (OTT) to DT soybean remains uncertain, but a reprieve from the intense heat experienced last week and growing weeds means that POST applications will continue to take place this week across the state. The last date for OTT applications of dicamba in DT soybean in Ohio is by the labeled soybean growth stage, or June 30th, whichever comes first. The date and growth stage cutoffs for the respective products are as follows:
- Engenia – no later than June 30th
- Tavium – V4 growth stage or through June 30th, whichever comes first
- XtendiMax – R1 growth stage or through June 30th, whichever comes first
At the plant level, soybean is at the V4 growth stage when there are four open trifoliates on the plant. A soybean plant is at the R1 growth stage when there is one open flower somewhere on the main stem. At the field level, a certain growth stage is achieved when greater than 50% of the plants within the field exhibit the designated characteristics. For detailed descriptions and pictures of soybean growth stages, check out this soybean growth stage guide. Information related to POST applications including maximum crop size and harvest intervals for corn and soybean can be found in Table 8 and Table 18 of the weed control guide, respectively. Scouting fields before planning POST applications can help determine management practices including product selection and application timing. As always, be sure to check all herbicide labels before treating fields.