Farmers must adopt a ‘zero-tolerance policy’ on black grass

Grass weeds are becoming more of a problem on tillage farms – according to Teagasc – and bromes, canary grass, ryegrasses and black grass have all been identified on many Irish farms this year.

Given the scale of the black grass problem in the UK, the research and advisory body advises Irish tillage farmers to adopt a zero-tolerance policy when it comes to controlling black grass on their farms.

This comes as black grass has become a costly problem in the UK, it says, and growers are spending €150/ha trying to control it.

Teagasc recommends that farmers implement a full control programme to tackle the problem. The multifaceted approach should include: rotation; rogueing; stubble cultivations; machinery hygiene; herbicides; and the possible introduction of a grass ley to eliminate the black grass problem.

Tackling a grass weed problem

According to Teagasc, one of the best methods to decrease weed populations in fields is to cultivate stubble after harvest. This encourages germination and reduces seed carry over.

Shallow cultivations, no deeper than 2cm, can encourage up to 80-90% of sterile brome and black grass seeds to germinate.

However, it’s important to identify the particular grass weed that you are trying to encourage to grow. This is important as meadow brome needs exposure to light for a period of time in order to break dormancy, whereas sterile brome needs to be covered to break dormancy.

In situations where farmers are not establishing cover crops, Teagasc says, there may well be an opportunity to carry out two or three cultivations and burn off with glyphosate before the establishment of the next winter or spring crop.

If catch crops are being established, an application of graminicide will help to kill off the grass weed and also reduce the competition to the cover crop. However, it’s important to ensure that the graminicide used is approved for the crop sown.