The two best fall-applied options for ryegrass and poa control in wheat are Anthem Flex and Zidua. Pyroxasulfone is providing the grass control in both these herbicides.
Anthem Flex may be applied as a true PRE right behind the drill. Oftentimes this use pattern is safe for wheat. However, some stand reduction may occur if wheat is planted and Anthem Flex is applied PRE to dry soil and a rain event happens shortly after sowing. As such, if rain is in the forecast wait and apply it later as a delayed PRE or early POST.
Zidua is typically applied delayed PRE to early POST. The earlier it can be applied the more effective it can be as it has no impact on emerged ryegrass. The earliest it can be applied as defined by the label is as a delayed PRE. The Zidua label defines delayed PRE as when 80% of germinated wheat seeds have a shoot at least ½” long until wheat spiking.
In past years, many have tankmixed metribuzin with Zidua or Anthem Flex. Metrubuzin can cause some significant wheat injury. Predicting wheat injury with metribuzin can be very challenging as so many factors are involved. Weather, wheat maturity, soil type, metribuzin rate and variety sensitivity all play a role on if injury will occur or not. As such I would recommend to NOT tankmix in metribuzin. The main weed target for metribuzin is poa. The pyroxasulfone should keep poa from emerging and therefore metribuzin does not provide much benefit. That weighed against the chance of considerable crop injury when applied to wheat just getting established really points to keeping
We are close to the end but a few still have acres left to defoliate. Others are considering applying another application to remove small amounts of leaf. Generally, most all of the harvestable bolls are open. Yields are off, in many areas considerably more than expected. At this point, we need to consider what we have in the field and what we might gain from another defoliation application. Most acres loosely break out to either 1,000+ lb per acre or far less than 1,000 lb per acre. The approach on these fields should generally be different. In this blog, I make a few comments and give a couple of examples of the best approach to wrap up 2025.
