- At a desk
- 24 Nov 2005
Ferric phosphate is also available as - Growing Success Advanced Slug Killer (pellets), Bayer Organic Slug Bait (pellets), Vitax Slug Death XL (pellets) and aluminium sulphate as Doff Slug Attack (granules).
The nematodes work in theory against snails, but in practice as snails don’t spend time in the soil so they do not come into contact with them.
When using copper, crushed minerals, etc be aware that slugs also travel under ground.
Copper has long been known to have a irritant and even toxic effect on slugs and snails, rather than an electric shock. In laboratory trials it has been found that both copper impregnated matting and copper foil repelled slugs with a 80-90% efficiency, although do not result in slug mortality. The effect of copper products varies with the species of slug tested and the width of the barrier. The width of the barrier should be greater than slug length. However these experiments were carried out under laboratory conditions with freshly brought products. In the garden situation it is important to keep copper strips free from debris if they are to remain effective. – the debris bit goes for any barrier.
Slugs and snails will easily go over sharp objects, those barriers that absorb moisture from the slugs are more likely to work, but need to be kept dry and free of debris.
When using beer traps take care they are not catching all your ground beetles too – many species of ground beetle eat slugs/snails, vine weevil larvae, caterpillars etc. Ground beetles themselves are food for hedgehogs etc.
I wonder if the Hedgehog preservation society is aware of this research: Gemmeke H . 1996. Effects of metaldehyde and methiocarb-poisoned slugs on hedgehogs. Mitteilungen aus der Biologischen Bundesanstalt fur Land und Forstwirstchaft Berlin Dahlem no. 317 p. 185-194. Abstract ‘The use of pellets containing metaldehyde to control slug populations on arable land involves the possibility that hedgehogs may come into contact with poisoned slugs or with pellets directly. The aim of this study is to determine whether hedgehogs kept in an enclosure feed on slugs treated with metaldehyde, and if so, display signs of poisoning. Of the six hedgehogs used, one consumed none, and one 12 of the slugs. The other four hedgehogs ate all or nearly all of the 200 treated slugs. Neither symptoms of metaldehyde poisoning or behavioural disorders were detected in any of the hedgehogs. All hedgehogs survived the study without negative effects and were released back into the wild in a good state of health to the place from where they were originally captured. The results demonstrate the following: some hedgehogs eat dead slugs either reluctantly or not at all, some hedgehogs eat metaldehyde-treated slugs in large numbers, healthy adult hedgehogs can consume up to 200 treated slugs without displaying signs of poisoning. The risk of secondary poisoning in hedgehogs due to the use of slug pellets treated with metaldehyde can be judged to be very low.’
'Trying is the first step to failure' H.J.Simpson