Sterile brome is a particular grass weed that has the potential to significantly impact on Irish tillage yields.

There are five different brome types in Ireland: sterile; great; soft; rye; and meadow.

Of these, sterile brome is the most widespread. It typically encroaches from the field margins to headlands and then the main field body.

Poorly inverted soil can result in brome appearance in ploughed fields.

In the UK, the economic threshold for sterile brome is just five plants/m².

Unmanaged brome can directly decrease yields, cause lodging, contaminate grain, increase control costs, and return large numbers of seeds to the soil seed bank that can re-infect land.

The advice from Teagasc is that now is the time to plan integrated weed management (IWM) strategies, which are largely based on cultural and judicious herbicide use, to tackle the brome problem.

Pre-harvest, growers should be looking for flowering heads and making accurate weed identification. At this time, the marking or mapping of weed patches is also important, and field margins should be inspected.

Teagasc also advises growers to never miss an opportunity to stop seed set, which means hand rouging small infestations and spraying off distinct patches.

During harvest, machine hygiene is critically important. Fields with high levels of weed infestation should be harvested last.

Post-harvest, there are a number of control measures that can be taken.

Shallow cultivation (max 5cm depth) immediately after harvest will result in higher germination of freshly shed seeds.

Thereafter, the opportunity to spray off these plants with glyphosate or to cultivate again will present itself.

Multiple stale seed beds can have an additive effect, provided there is time to do it.

In other situations, a chopped straw cover spread evenly may provide adequate darkness and moisture to trigger rapid germination of brome seeds.

Delaying autumn drilling of winter cereals beyond the mid-point of October would mean that a new crop is going into the ground at a date beyond the main germination flush of brome seeds.

Ploughing to a depth of 15cm or more can bury seeds below emergence depth. Unlike other weeds, repeated ploughing may carry less risk of viable brome seeds to resurface. Bromes are more difficult to control in non-inversion systems.

Shallow cultivation to establish a stale seedbed can be very useful in direct drill or strip till situations. In deep non-inversion tillage, the weed seeds are distributed through the soil profile to the depth of cultivation.

This may bury seed, resulting in them being added to the seed bank rather than reducing their numbers through immediate germination.

Where field margins are concerned, establishing a perennial cover or grass margin will provide competition to slow the growth of brome from headland and reduce seed return.

Such field margins should be mown in the following May and September to encourage grass tillering and prevent seed return.