The threat of black-grass to growers in Scotland has been put into perspective by AHDB Cereals & Oilseeds.

The organisation has also published two animations illustrating ways to balance chemical and non-chemical black-grass control methods.

The new ‘perspective’ publication – ‘Is black-grass a threat to Scotland? An overview of the situation’ – was prepared in response to reports of black-grass creeping into Scotland.

The publication concludes that black-grass abundance is relatively low in Scotland and a rapid rise in populations – such as seen by growers on heavy-textured soils in the south and east of England – is unlikely to occur due, in part, to differences in farming systems.

Key farming system differences include:

1. A relatively high number of mixed farms, allowing affected fields to be put to grass

2. A greater use of ploughing, helping to bury seeds below the critical depth of 5cm

3. More spring cropping, allowing good control opportunities outside the crop

Dr Paul Gosling, AHDB Cereals & Oilseeds Research Manager and publication author, said: “These differences are interesting as they should make Scotland’s farms more resilient to black-grass.

“In fact, these management approaches are among those recommended for growers with black-grass issues in England.

“But, as experience in England has shown that a small black-grass problem can quickly get out of hand, particularly where they are resistant to herbicides, Scottish growers must remain vigilant.”

Action points

To help reduce black-grass spread in Scotland, growers are being asked to:

1. Apply good hygiene practices to reduce the risk of black-grass introduction – eg ensure machinery is thoroughly cleaned before coming on the farm, and only use straw and seed from reputable sources

2. For low black-grass populations, hand rogue or spray off patches

3. Get suspected herbicide-resistant populations tested

Resistant black-grass

In relation to resistance, some black-grass populations in Scotland are likely to already carry a degree of resistance and laboratory confirmed cases of resistance have been found in the Borders.

Dr Gosling said: “The origin of black-grass resistance in Scotland is not clear, but the sheer resistance pressure in England means cross-border contamination is a much more likely source of resistance than native populations. This is why good hygiene practices are so important.”

Weed animations

Two new weed animations, developed as part AHDB Cereals & Oilseeds ‘cultivating success’ display at Cereals 2015, have also been published online.

A ‘Black-grass solutions to the problem’ video looks at the potential reduction in black-grass that can be achieved by integrating non-chemical methods with herbicides.

A ‘Minimising the risk of glyphosate resistance’ video illustrates four on-farm actions – ‘prevent survivors’, ‘maximise efficacy’, ‘use alternatives’ and ‘monitor success’ – to prevent glyphosate resistance developing in UK weed populations.

Dr Gosling concluded: “The solutions to black-grass featured in the animation were developed from research conducted in the South and East of England.

“Due to Scotland’s cooler and wetter climate, some of the solutions featured are not as appropriate.

“Delayed drilling, for example, is not only likely to be less popular but may also be less effective as black-grass seed dormancy is likely to be higher in Scotland.”

To access the latest publications, videos and other black-grass management resources, visit AHDB Cereals & Oilseeds’ dedicated web page: cereals.ahdb.org.uk/blackgrass