September has continued to be as wet and gloomy as last month, but these conditions have been heavenly for slugs. An explosion in slug numbers across the country has resulted in prized vegetable patches being devastated by an onslaught of slugs in what should have been a glorious growing season.

Slugs need to keep their skin moist, but unlike snails they do not have a shell to retreat to when conditions turn dry. Instead, they hide under bits of wood, leaves and down cracks in the soil. But in the recent mild, rainy weather they have been able to slither and slide all over the ground in broad daylight. The heavy rains make it difficult to use slug pellets effectively, although research at Newcastle upon Tyne University shows that garlic oil is a good alternative treatment.

The rains and the resulting slug attacks could not have come at a worse time for arable farmers. New crops such as winter wheat and oilseed rape are being planted now, and are being attacked mercilessly. “Oilseed rape is particularly vulnerable because the slugs love it and, once attacked, it doesn’t recover,” says Dr Richard Meredith, of Bayer CropScience. The most striking of the marauders is the big Arion ater group of slugs that range in colour from orange to black and are up to 10cm (4in) long. “The big slugs especially are extending their comfort zone, which is usually around the edges of fields, and they are now foraging further infield in the wet weather,” Dr Meredith adds. However, the smaller, less visible slugs are the worst villains. Because they are so numerous, they do most damage.