nematodes are a DIY slug killer

DIY slug killer taps into the power of a natural soil predator

Toby Buckland, 3 Aug 2011, writes: There are 29 species of slug in Britain, but just four give the rest a bad name: the common garden slug, a leathery gunmetal grey and the length of your little finger; the fat, sickly grey field slug; the black slug, the biggest (and sometimes rust coloured) and keeled slugs, which have a ridge along their backs and a taste for potatoes.

Snails do their fair share of damage too, but, while snails chew the edges of foliage and open up the holes already made by slugs, it’s the slugs’ rasping mouth parts that scrape away and puncture the surface of foliage and turn your hostas into doilies.

Slugs are prey to not just frogs, hedgehogs and birds but microscopic bacteria and nematodes that live in soils. It’s these nematodes (microscopic eelworms) that gardeners have been buying as a form of biological control since the early nineties. Mail-order sachets of nematodes infected with deadly mollusc-killing bacteria temporarily raise the proportion of nematodes and bring down the slug population.

However, there is also an allotment-owner’s trick for making your own slug-killing nematode potion, using nothing more than a bucket, some weeds, tap water and the slugs from your own garden.

How to make your own slug killer

Search for slugs during the day under pots and stones