Excelsior prides itself on looking for environmentally friendly practices, and this extends to pest control. Far and away the most costly pest on Excelsior is the humble snail. For the past decade we have moved towards using less and less herbicides, and avoid sloughing as this has a detrimental effect on soil structure. This is known as minimal tillage. The benefits are a more “living” soil, as there is plenty of food for earthworms (which burrow down and open up the soil, allowing oxygen and root penetration), as well as micro – organisms, which help the plant access nutrients.
The major drawback is that this provides the perfect environment for snails to breed. There is plenty of shelter, and food all year round. And can they breed! A snail is hermaphroditic (both sexes can lay eggs) and each snail lays approximately 50 eggs each.
Now the harmful snail is the non-edible small white snail called Theba Pisana. It absolutely thrives in the arid lime soils of the Robertson area. It uses the lime to produce a very hard shell, which makes it fairly unpalatable for the traditional snail predator – the duck. Ducks work well for controlling some species of snails and slugs, but not the white snail.
We use a poisonous bait (mixture of Bran and poison) that dehydrates the snail, and is quite effective. The problem is that animals, especially dogs, are also fond of it, and it can kill them. Using poisons is also not good for the environment, and it is damn expensive.
I have been searching for a softer cure for snails, and I believe that I have found one. Iron is poisonous to snails. It is the ultimate diet pill for them, as it completely suppresses their appetite, until they starve to death. I use a common agricultural fertilizer called iron sulphate, and mix it into the bran in place of the normal poison. This year I have done about a third of the farm with this mixture and will monitor the outcome. But so far it looks extremely promising, and the added bonus is that it is very cheap.