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Extract from mosses helps to protect crops from snails

© Esther Wullschleger

Snails in the garden can be an awful pest, if they become too numerous and like to feed on crop plants. However, gardeners with some consciousness for natural processes do not like to apply poison against snails, since this also harms animals which eat snails, such as hedgehogs. Other options are the well-known beer traps (but did you ever hear of the hedgehogs in Great Britain that showed signs of having received too much alcohol?), collecting snails repeatedly during dusk or dawn (which means a lot of work), or buying snail fences for small garden areas.

Mild poison made of natural ingredients is another option to keep snails away from the crops. With regard to this, a German group of researchers from the University of Bonn made an interesting finding about a year ago. These botanical researchers were studying mosses, and the ingredients that protect these fragile miniature plants against enemies such as fungi, bacteria and ? snails.

Interestingly, mosses are preferably growing in humid and shady areas, were fungi grow very well, and where snails like to be. Still, they hardly ever get eaten by snails, nor infected by fungi or other diseases. Tens of years ago already, attentive naturalists have asked themselves why mosses remain so unharmed, while they have only soft tissue without any protection through spines or thorns. It was suspected that these plants produce some chemicals which make their tissue poisonous to herbivores, and antibiotic. Actually, this was not even a new insight. It is said that American Indians knew long ago that mosses have antibiotic effects. They used mosses to treat wounds in order to avoid inflammation.

Professor Jan-Peter Frahm and his research team at the University of Bonn made the first experiments with crop plants to prove a beneficial effect of moss extract. First, they sprayed plants infected by fungi with moss extract. To their astonishment, some of the extracts they tested in the experiment were even more successful than industrial antifungicids!

In a later experiment, two lettuce leaves were offered to snails, one sprayed with moss extract and the other not. The snails absolutely did not like the moss ingredients, and completely avoided lettuce with moss flavour. Snails are not killed by moss extract, but it completely spoils their appetite for the sprayed crops.

Under the name ?Lebermooser?, moss extract has been brought to the European market as a non-polluting ingredient to protect and strengthen crops. The German producer suggests to spray crops every 14 days, or more often if it rains heavily. Of course, one might try to produce moss extract on one?s own. This is a bit tricky, because not all mosses have the same striking effect. Also, some mosses are rare and deserve protection status, thus they shouldn?t be collected in large quantities.