Source: Dr. Alyssa Essman
Crop progress is highly variable this year. Some early planted crops have emerged and have had decent growth following recent rains. Dry weather has delayed the emergence of some later planted crops. This means there will also be variability in growth stages, which can have implications for POST application timings. The deadline to apply dicamba over-the-top (OTT) in Ohio is coming soon. For OTT applications of the dicamba products labeled for this use, the cutoff is up to and through June 30th, or the labeled growth stage. Below are the cutoff dates and/or soybean growth stages for the different products.
- XtendiMax – R1 growth stage or through June 30th, whichever comes first.
- Engenia – no later than June 30th
- Tavium – V4 growth stage or through June 30th, whichever comes first.
A soybean plant is at the V4 growth stage when there are four open trifoliates. The R1 growth stage occurs when there is one open flower somewhere on the main stem. See here for detailed descriptions and pictures of soybean growth stages. Table 8 and table 18 of the weed control guide have information related to the maximum crop size and harvest intervals for POST applications in corn and soybean, respectively. As always, it’s important to scout fields before planning applications and follow the herbicide label guidelines.