NovaChem > Industry News > 2013 > Black Grass

Black Grass

Published on 16/09/2013

FAR is working with fellow cropping industry stakeholders to deal with a potential incursion of the invasive weed black grass (Alopecurus myosuroides), after the accidental spillage of contaminated seed between Ashburton and Methven last month.

FAR, the Ministry for Primary Industries, Federated Farmers and E-Can are working together to identify specific areas or properties along the stretch of road that are most at risk, and to develop a surveillance plan and an eradication plan should any plants establish.

Our understanding is that the amount of seed that was spilled was small and that the percentage of black grass contamination of that seed was low. This considerably reduces the risk of this invasive weed establishing. However, given its potential economic impacts, it is vital that all reasonable steps are taken to prevent establishment.

Black grass, or meadow fox tail is a serious invasive weed of winter crops in the UK and Europe, where it has developed resistance to many herbicides and is thus, very difficult to control in a number of crops. It competes with crops for nutrients, light, water and space, out-competing crops and reducing yields.

The contaminated seed lot has been isolated and returned to its country of origin.

Black grass is an annual grass that can grow up to a metre high (ie. it can grow above winter crops). The leaves are hairless, with an open sheath, and rolled in the bud. The sheaths can be green or purplish. The seed heads are usually reddish-purple in colour, giving the appearance from a distance of black grass. The seed are smaller in diameter in proportion to their length than those of other perennial species commonly planted for pasture and range from approximately 2.5 -12.5 cm tall and 0.3 - 0.6 cm in diameter.

Germination of the spilled seed is most likely to occur from now, right through to April next year. Black grass can go from germination to full maturity within 100 days. Therefore, any black grass would be most visible from November 2013 to April 2014. Black grass will begin to set seed around this time, and to prevent further onward spread of the seed, early reporting is vital. Farmers can assist with surveillance and reduce the chance of black grass becoming established in the area by keeping an eye out for any sign of the pest and if found report it immediately.

Further details about this incursion can be found on the attached fact sheet, or on the FAR website.

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