26 November 1999

Carabid beetles bash weeds

CARABID beetles are usually associated with beneficial effects on insect populations in crops. But new research suggests they can help deplete weed seed-banks too.

In laboratory tests, beetles offered seeds and insects chose to eat a diet of up to 60% weed seeds. Some species showed clear preferences for certain weed seeds.

"One really liked field pansy," says Josephine Tooley, a Reading University research student working on the project. Bigger beetles went for wild oats, and they all liked blackgrass seeds. Unfortunately, none liked cleavers.

Growers would do well to take note of this double barrelled benefit of the beetles, she says. "There is a good possibility beetle-banks will help weed control. Farmers should take a lot more care to preserve beetle numbers."

The work is being field-tested in Leics and Berks this year. "The results back up the lab work so far," she concluded. &#42