Brome, Downy (Bromus tectorum L.)

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Table of Contents

1. History
2. Life Cycle
3. Distinguishing Characteristics
4. Control in Corn
5. Control in Soybeans
6. Control in Winter Wheat

History

A very difficult to control species in cereal crops. Downy brome is often found on lighter texured, sandy soils.

Life Cycle

Annual or winter annual. Reproducing only by seed.

Distinguishing Characteristics

Upon first glance downy brome can be confused with wild oats, however wild oats will have "dark coloured" nodes. Downy brome is distinguished from other brome grasses by its hairy texture and its thin, long-awned spikelets.

Downy brome Pictures
Each thumbnail image links to a larger image

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Herbicide Control in Field Corn

Field experience has shown that either a pre-plant cultivation or burndown with glyphosate should control downy brome in field corn. However, it is possible for a second flush of downy brome to germinate. Two post-emergent treatments were tested in conventional corn and ULTIM provided the greatest activity on downy brome but did not provide control of this species (Table 1).

Table 1. Downy brome control in corn with ULTIM and OPTION.

Active Ingredient	Trade Name (application timing)	% Control
nicosulfuron/rimsulfuron	ULTIM	70
foramsulfuron	OPTION 35 DF	50

Source:
Mike Cowbrough, OMAF.

Number of Trials:

Table 1 based on a summary of 1 field trial .

Herbicide Rates:
Rates used in this trial are listed in OMAF Publication 75 - Guide to Weed Control.

Weed Stage:
Downy brome had 2-4 tillers and was approximately 5 cm in height at the time of application.

What has been your experience?
We want your feedback. Let us know what you have experienced with these or other products, as well as any other effective management strategies.

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Herbicide Control in Soybeans

A pre-plant glyphosate brundown or cultivation should provide good control of downy brome in soybean. However, it is possible for a second flush of downy brome to germinate. Three post-emergent treatments were tested and ASSURE II provided very effective control of downy brome while VENTURE L and POAST ULTRA offered only supression (Table 1).

Table 1. Downy brome control with three post-emergent soybean herbicides.

Active Ingredient	Trade Name (application timing)	% Control
quizalofop-p-butyl	ASSURE II	99
fluazifop-p-butyl	VENTURE L	70
sethoxydim	POAST ULTRA	50

Source:
Mike Cowbrough, OMAF.

Number of Trials:

Table 1 based on a summary of 1 field trial .

Herbicide Rates:
Rates used in this trial are listed in OMAF Publication 75 - Guide to Weed Control.

Weed Stage:
Downy brome had 2-4 tillers and was approximately 5 cm in height at the time of application.

What has been your experience?
We want your feedback. Let us know what you have experienced with these or other products, as well as any other effective management strategies.

 

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Herbicide Control in Winter Wheat

Downy brome is extremely problematic in cereal crops, particularly fall planted wheat and barley. There simply are no herbicides that control downy brome in-crop. Pre-plant glyphosate applications are somewhat effective at keeping downy brome populations from getting out of hand as this weed will germinate in the fall. However, one can also expect germination in the spring and products like ACHIEVE L do not offer any control of downy brome. Research conducted by R.E. Blackshaw in Alberta demonstrated that low rates of metribuzin were effective at controlling downy brome when applied in the spring. However, Dr. François Tardif and Peter Smith (University of Guelph) duplicated this work in the spring of 2004 and observed that although metribuzin provided the best control of all products tested, it was nowhere near commercially acceptable. Trials for the control of downy brome in Ontario are ongoing and data will be presented as it becomes available.

**SENCOR (metribuzin) is not registered for use on winter wheat in Ontario.

References:

Blackshaw, R.E. 1993. Downy brome (Bromus tectorum) control in winter wheat and winter rye. Canadian Journal of Plant Science. pp 73:185-191.

What has been your experience?
We want your feedback. Let us know what you have experienced with these or other products, as well as any other effective management strategies.

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