A weed wiper kit fitted to conventional sprayer booms could offer an alternative approach to controlling costly blackgrass, according to early on-farm trial results.

The search is on to find other ways of taking out herbicide-resistant blackgrass in infested fields, as traditional methods are struggling to kill the weed on many farms.

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Weed wiping has existed for some years in a number of other situations, such as for the control of rushes in wet grassland, says Mark Spicer, managing director of Norman and Spicer Agriculture, part of the Hutchinsons Group.

Wipers work by physically applying herbicide through direct contact with weeds and they rely on the target weed towering above the crop, just like blackgrass when it starts to flower.

However, weed wipers have not been practical for covering large areas of cereal crops, with machines designed for small areas of pasture.

Watch a video of the tractor-mounted weed wiper in action.

US technology

However, the technology is now available for use in arable cropping in the US, where Smucker is manufacturing kits that can be retrofitted to conventional boom sprayers.

“It is a piece of kit that attaches to the back of the boom which is made up of a row of sponges that are gravity fed with herbicide,” explains Mr Spicer.

However, no such kit exists in that format here in the UK, which led to a collaboration between Mr Spicer and Boston Crop Sprayers (BCS). Together, they have conducted a field trial in Bedfordshire with a similar machine of their own creation.

David Hildred, managing director of BCS says: “There is no doubt that we have been able to kill off a large amount of the blackgrass and prevent a huge seed bank being returned to the soil.”

Further work

“However, we need to do some further work to quantify this, but the reduction is significant enough to warrant spending more time on the concept.”

He went on to explain that for the method to be effective, timing and amount of application of herbicide are critical.

The blackgrass should ideally be in flower and not filled, and he says there needs to be a significant flow of herbicide through the machine to properly wet the plant.

In addition, there needs to be a significant gap between the weed and the crop to ensure the crop is not being wiped out simultaneously. This would require a good plant growth regulator programme, he adds.