Ryegrass And Poa Management In Wheat

DR. LARRY STECKEL

 JACKSON, TENNESSEE

The two best fall-applied options for ryegrass and poa in wheat are Anthem Flex and Zidua.  Pyroxasulfone is providing the grass control in both these herbicides.   Anthem Flex can be applied as a true PRE right behind the press wheel.  Keep in mind there is some chance of wheat injury from this new use pattern if a rain occurs shortly after planting.  As such, if rain is in the forecast wait and apply it later as a delayed PRE or early POST.

 Zidua can be applied in wheat only as a delayed PRE.  The definition for delayed PRE on the Zidua label states when the shoot is at least ½” long.

 Many last fall tankmixed metribuzin with the Zidua or Anthem Flex.  This caused some significant wheat injury last November.  Predicting wheat injury with metribuzin in wheat 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. 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 metribuzin out of the tank.

Another option would be Axial Bold. It performs best in the true POST emerge option.  It can be applied any time after the wheat and ryegrass have emerged. Smaller ryegrass is easier to control so fall applications of Axial Bold can be very successful.  Axial Bold is typically applied in March which can also work but is not as consistent as fall or early winter applications.

 Several folks have asked about controlling grape hyacinth in wheat. Grape hyacinth is often mistaken for wild garlic or onion as it has a similar leaf characteristic and establishes from bulbs. Also, like wild garlic, it is a low growing perennial that is not that competitive to a good wheat stand.  Unlike wild garlic, grape hyacinth does not produce aerial bulblets that will cause dock at the granary.  Due to its modest competitive ability and not causing dockage, a spray application for grape hyacinth alone will rarely be warranted.  If it is a very thick stand then a pint of 2,4-D applied after the wheat is fully tillered POST is the best option. ∆

DR. LARRY STECKEL: University of Tennessee