Be prepared to raise your game against a rising tide of brome invading arable fields as less ploughing is carried out – that’s the view of Alistair Gordon, regional technical manager for Ross-shire-based agronomy firm, Robertson Crop Services, part of the ProCam group.

Increasing use of minimum tillage as a cheaper alternative to ploughing, is seeing brome worsening, he reckoned, as shed brome seed is no longer being buried beneath its depth of germination. As a common weed species that inhabits field margins, he said headlands are where infestations usually start.

“Increasingly, I am seeing that extra attention to detail is needed to stop brome invading from field margins,” added Mr Gordon. “On the positive side, seeing brome appearing in headlands first gives you a kind of early warning before it spreads further into the field. The problem can be managed, but you have to stay on your guard.

“If you are not ploughing whole fields, at least deep plough a few widths around headlands to bury brome seed. If possible, use stale seedbeds to kill off emerging brome plants before the next crop. And crucially, pay attention to detail with in-crop herbicide application, which can be in autumn or winter but in some cases can be in spring.”

With brome in winter cereals, Mr Gordon said that while a programme of pre-emergence and post-emergence herbicides can be used in winter wheat, only pre-emergence herbicide chemistry is available against brome in winter barley. Therefore, he avoids planting winter barley in fields where brome is a serious concern.

For pre-emergence herbicides, he reported having success with a mixture based around flufenacet and pendimethalin. As well as various grass weeds, this had the advantage of also controlling various broadleaved weeds, leaving fewer to tidy up in the spring.

“With some herbicides, there can be an opportunity to save money if you are careful, for example by using a full dose around the headlands but a half dose over the rest of the field,” he said. “Post-emergence in winter wheat, I tend to follow-up with a spring application of a mesosulfuron + iodosulfuron product.”

Looking at brome in winter oilseed rape, he said that even though it is a break crop, it is important to control grass weeds in it, because you can’t see what is surviving beneath the tall canopy. He targets brome in it with the residual herbicide propyzamide.

Once again, he said there could be the opportunity to save costs by focusing application on the headlands if the weed is caught early enough, before it invades the rest of the field. “Propyzamide also has the benefit of controlling certain other grass weeds and broadleaved weeds, but it needs applying in the right conditions and at the right time.”

“Generally, post-emergence herbicides perform better when weeds are growing, which means warmer conditions, while residual herbicides, such as propyzamide, are better applied when conditions are cooler, to get the best residual life in the soil.

“Don’t overlook the importance of good herbicide application. Similarly, keep the boom height down to 50 cm for the best soil coverage, plus use the correct nozzles and spray at a maximum of 12kph. Going faster can reduce efficacy due to spray drift. Another risk is brome seed being spread into your fields by machinery coming from other farms without first being cleaned down.

“Even if you plough, if you don’t do it well enough you can still get brome, especially on the turning points where you often see it coming up with volunteers.”