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Downy Brome Control (05/19/16)

Question: Does Rimfire Max mixed with Express work better on downy brome than when using Rimfire Max alone?

Downy Brome Control

Question: Does Rimfire Max mixed with Express work better on downy brome than when using Rimfire Max alone? I understand that using two SU herbicides can overload the wheat plant and cause significant injury. I have heard that when spraying Express alone that you get 50% biomass reduction and 50% seed production of brome species. Can we increase downy brome control by using Express with Rimfire Max, or Powerflex, or Beyond in IMI wheat?  Will we increase plant injury?

Answer by Dr. Kirk Howatt, NDSU Weed Scientist: I do not have specific experience but increased control of downy brome from SU herbicides is possible if applied early.  Once downy brome heads start to show it is too late.  Express has helped on other grasses when ALS products have been used.  Bromes are susceptible to ALS so the additional ALS product should help.  Even though Express is for broadleaf weed control, there has been observation over the years of grass activity, especially young seedlings.  Also, yes, the added ALS product can lead to crop response.  But wheat has such high tolerance that injury is not often observed and seldom is yield affected unless timing was late for the grass ALS herbicide anyway.

Rich Zollinger

Extension Weed Specialist

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