21 July 1995

Is blackgrass bent?

CEREAL growers on Wold land who suspect they have herbicide-resistant blackgrass in early spring should take a closer look – chances are its black bent.

Slows combining

The weed has spread rapidly in the past few seasons, says Aubourn Farming agronomist Bridget Carroll. It harbours ergot, encourages take-all, slows combining, and competes with potatoes and sugar beet, cutting yield and hindering harvest.

It looks very similar to blackgrass during spring germination, but is slightly more prostrate and spiky, and goes on to form telltale rhizomes in mid-spring.

Control is tricky. Post-harvest glyphosate applied "when the crop is green and actively growing" is the only option in cereals. But it can be killed with break crop graminicides, notably in rape, Miss Carroll advises.