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Growers, Now is The Time for Winter Annual Grassy Weed Control

Winter annual grass management should be conducted in the fall because these hard to control grasses can be too far ahead of you in the spring (especially downy brome). There are several options for fall grassy weed management.

Herbicide options include: Zidua™, Outrider™, Anthem Flex™, Olympus™, Powerflex™, Sencor™

One weed, in particular, that is difficult to control in the spring is downy brome. Several research studies have been conducted for the optimal control of downy brome in cereal crops (see two of these below).

Downy Brome Control %
Treatment Fall applied Spring applied Fall vs Spring 
2 oz PowerFlex HL 90% 28%  63% increase
0.9 oz Olympus + 3.0 oz Metribuzin 80% 18% 63% increase
0.9 oz Olympus 71% 45% 26% increase
0.67 oz OutRider 69% 31% 38% increase
6 oz Metribuzin 51% 19% 32% increase
3 oz Metribuzin 39%
CHECK 0% 0%
Weed Pre-emergence Weed Post-emergence
% Brome control Product Rate (oz/a) Product Rate (oz/a)
98 A Zidua 1.50 Powerflex HL

+ M90 + UAN 32

2.0

0.25% + 2 qt

85 ab Anthem Flex 3.50 Osprey +

+ M90 + UAN 32

4.75

0.50% + 2 qt

84 ab Powerflex HL

+ M90 + UAN 32

2.0

0.25% + 2 qt

81 ab Zidua 1.50 Osprey +

+ M90 + UAN 32

4.75

0.50% + 2 qt

74 bc Axiom DF 10.00 Osprey +

+ M90 + UAN 32

4.75

0.50% + 2 qt

67 bc Anthem Flex 3.50
60 c Zidua 1.75
60 c Zidua 1.50 Outrider

+ M90

0.66

0.25%

56 c Zidua 1.95
55 c Zidua 1.50
43 d Axiom DF 10.00
43 d Osprey +

+ M90 + UAN 32

4.75

0.50% + 2 qt

26 e Olympus

+ M90

0.9

0.50%

19 ef Outrider

+ M90

0.66

0.25%

0 f Untreated
0 f Untreated
If you have not treated your downy brome, do so soon. Several of the treatments are pre-emergence and you may be missing the boat on some control if you have not applied, however, you will be able to control later emerging flushes. Always be wary of herbicide resistance and try to use multiple modes of action when combatting these fall grasses.

Additional Resources

View our Common Weeds List and our Integrated Management of Downy Brome in Winter Wheat (pdf) publication.


Washington State University