we do have slugs and snails on our plot but they cause little damage - we won't use pesticides - this piece about Iron Phosphate may be of interest:
http://www.hostalibrary.org/firstlook/RRIronPhosphate.htmI don't know if I'm allowed to do this but here's a bit of a blog from a friend who now lives in France:
The biggest problem is that the 'traditional' method of control has had a 'catch 22' effect, whilst killing the slugs and snails effectively it also led to a decline in the predators of these animals. The second major factor is the UK's passion for keeping cats. A Basque 'soils' man who was working with us last year was astounded by the size of the UK cat population and directly blamed them for our slug and snail problem. He was adamant, (although I doubt this is backed up by any academic research), that as the Basque people had to resort to eating all their cats during the Spanish Civil War the population of cats is minimal and as such the traditional predators of slugs and snails, namely, bird's particularly Thrush, Slow Worms, Hedgehogs and Toads are common and will keep the gastropods under control.
I would not dare to utter that there needs to be a cat cull in the UK, to satisfy horticulture, as I do not wish a lynch mob out to get me.
Living in France it is very evident that there is little problems with slugs and snails, (whilst the common guess at this would be that they eat them - this is not true, where I am at least). The cat population is lower here, but I don't think this is the answer either.
The French are brilliant at 'sustainable' gardening, there is no altruism to it, they are certainly not all green minded either. It simply makes sense and costs nothing. As such around most of the vegetable plots and in 'Potager' gardens, they have an arsenal of little habitats constructed into gardens to make suitable homes for the predators they need to encourage.
Toads are treated with reverence here, rightly so, their ability to significantly reduce a population of slugs is fantastic. As such holes dug into the ground at a slight angle can be found everywhere. The walls of these holes are usually old slates and in some cases I have seen sections of concrete drainage about 500mm long just inserted into the ground with a loose flat stone on top. These little burrows can house up to 5 or 6 large toads at a time.
Dry stone walls or habitat piles are deliberately constructed to allow for habitats, slow worms are very common and are voracious predators on both slugs and snails. A collapsed section of wall I have seen near here actually has small chambers carefully built into the bottom. The entrances are built to encourage hedgehogs.