Anti-slug bugs lose the battle

The slug, the gardener's most persistent and ravenous enemy, has scored another victory over man's attempt to control it. A highly touted biological predator, the nematode, was withdrawn from the market last week because it has lost its appetite for the slimy creatures.

For thousands of gardeners, this will mean another summer of despair as slugs wreak havoc on lettuces, dahlias and the many other plants they thrive on. And it will prove costly for MicroBio Ltd, the only company that breeds the nematodes.

Two firms market them - Defenders and Miracle Garden Care. They have between them taken thousands of pounds' worth of orders which will have to be refunded.

Nematodes were introduced three years ago as the ultimate answer to the slug problem. They are tiny creatures that burrow into the slug's skin, then breed profusely in its stomach. The infected slug stops eating in about three days and is usually dead within a week. The garden can be virtually cleared of slugs for most of the summer.

Nematodes are expensive - pounds 11.20 to treat 20 square metres - but in their first year they proved highly successful.

Last year, though, they lost most of their sex drive and refused to breed inside the slugs. Graeme Gowling, product manager at MicroBio, explained: "Something happened to the bacteria in the production process and we have to go back and trace what it was."