Control of Brome Grasses in Cereals

Article largely based on HGCA guide on Bromes, for more information see http://www.hgca.com/media/433528/is31-identification-and-control-of-brome-grasses.pdf

Brome grasses are important weeds as they can cause up to 40% yield loss and can slow harvesting in winter cereal crops. Brome is historically associated with minimum tillage continuous Winter Wheat. However, with the increase in popularity of Winter Barley, they have become an increasing problem in some fields. Controlling the problem chemically is particularly difficult in Winter Barley as there is a limited selection of herbicides with activity against Brome species that can be used when growing Winter Barley. So, if you have Brome on your farm, how do you go about controlling it?

Key point: Brome grasses are economically important weeds in winter cereals and are difficult to control using chemicals alone (particularly Winter Barley), therefore cultural control is critical.

Cultural control
Post-harvest control
The first step is to identify the species of Brome as there are two groups which require different post-harvest methods to maximize control.
1. The Anisantha types (sterile and great brome) have long awns and large drooping panicles (flowering heads)
-Ploughing best for good control
-If not ploughing, shallow cultivate as soon as possible after harvest, to bury seeds and encourage germination. Spray off seedlings with glyphosate pre-drilling.
-Delaying drilling will significantly improve control.

 

2. The Bromus types (meadow, rye and soft brome) have short awns and tighter, upright panicles.
-Leave seeds to ripen on soil surface for 1 month before cultivating.
-Shallow cultivate after a month, then spray off emerged seedlings with glyphosate.

Key point: You need to identify the type of Brome on your farm because there are different methods to control the two types.

Preventing seed spread
• Manage your headlands and field margins if Brome present as harvest and subsequent cultivations can move seed up to 50 metres into the field.
• Brome can be introduced via contaminated seed, ensure you use Brome free seed (Irish certified seed is Brome free).
• Be careful with straw from infested fields as it may contain substantial quantities of viable Brome seeds (more likely if the Bromus types-meadow, soft and rye brome are in the field).

Using the whole rotation
• A non-cereal break crop enables use of graminacides to control Brome. A spring crop allows stale seedbed or fallow techniques and encourages germination.
• Seedlings can be killed using glyphosate pre-drilling.

Maximising seed loss pre-drilling
• Seeds buried by ploughing to 15 cm depth cannot emerge, so ploughing provides effective control. However, high levels of brome are difficult to bury as seeds clump together and can be flicked up during ploughing onto freshly ploughed land. Slow ploughing results in better burial. Annual ploughing can be effective but a small proportion of seeds can survive at plough depth from one autumn to the next.
• Delayed drilling significantly improves control.
• Sow at higher seed rates to increase crop competition.

Managing field margins
• Bromes quickly colonise bare patches in hedge bottoms or field boundaries. Sow a perennial grass mixture in these areas to prevent bromes establishing.
• Mow field margins containing Bromes within 2–6 days of flowering to prevent viable seed forming (April onwards). Ideally, mow before panicles begin to emerge. Cutting before 1 March and after 31 July provides reasonable control but avoids bird nesting.
• Do not use uncultivated strips where Brome is confined to field margins. Avoid herbicide spray drift into margins, as this creates bare patches.

Chemical control
Chemical and cultural control should be integrated as there is a limited range of herbicides is available with activity against Bromes in cereals (see table below).

Get in touch 

For further help and advice contact your local Agri representative

Meet all our representatives