KILLER SNAILS

The Iberian forest snail ("Arion Lusitanicus", known popularly in Denmark as the killer snail) is a brown snail with a voracious appetite. In its native southern Europe and Spain, the hot, dry climate and natural predators combine to keep down the numbers. But here in wet Scandinavia, there is no natural predator. So, if they manage to survive a cold winter, their numbers explode during the summer, threatening both local kitchen gardens and the domestic black forest snail ("Arion Ater").

It is thought that the invasive species arrived in Scandinavia through the importation of plants. It was first seen in Sweden in 1975, in Norway in 1988 and in Denmark in 1991. In each country the pattern was the same; half a dozen years of low activity followed by a huge increase in numbers. With no natural predator, humans' killing them is the only option; yet that is not without problems, since killer snails are also cannibalistic, so dead snails merely attract more of the same. My post-badminton beer sessions have often been taken up with animated discussions of the best way to kill these wretched creatures. Beer traps appear to be the consensus weapon of choice; though I have recently heard of a foodstuff that constipates them so much that they die of starvation (as also happens to the next snail that eats its dead companion).

Although we have a wood on our property, I have never seen a killer snail in the 10 years I have lived here. Until this summer. So the problem has finally reached us.

Snails of all sorts tend to "come out" just after it has rained. It has rained for most of today, and I went out on a bike ride this evening after it had stopped. Crikey, there were a lot of snails out on the roads, more of them brown than black, I'm afraid. A lot of the brown ones died under my front wheel as I whizzed along. Just another billion to go.

When I got back, I went down and checked my kitchen garden, and found to my horror three killer snails sitting on top of my lettuces. The pesky things had managed to cross the ditch that I had dug around it, so it shows how resourceful they are. The three died a nasty death, being speared by my garden fork. I suspect that they were the first executions of many.

Walter Blotscher