What’s wrong with slug pellets?

• Slug pellets are poisoned cereal chunks. Metaldehyde and methiocarb — the two most common slug poisons — would not on their own be an attractive proposition to slugs. Slugs would rather eat nice young shoots than poisons so manufacturers have to put the poison in a bait, and by law the bait must be more attractive than plants. Unfortunately these cereal chunks also attract dogs, birds and beetles — causing death or injury if consumed in large numbers.

• Manufacturers claim that slug pellets used correctly will not kill animals. If slug pellets are spread out according to the instructions on the packet, dogs and birds will not consume sufficient quantities to cause serious injury or death. John Hancock, Sales and Marketing Director for pellet manufacturer Doff adds, "pellets are deliberately made unattractive to all non-target species using elements such as colour — blue being unattractive to birds — and bittering agents and animal repellents."

• Slug pellets do kill and cause distress to animals. Here are the facts: there are no national statistics for animal poisonings, as they are not collected by anyone. However, there are two sets of records that give us some indication of the level of slug pellet poisoning in Britain. These are: an annual government study into the agricultural use of pesticides called Pesticide Poisoning of Animals; and a set of statistics from the Veterinary Poisons Information Service (VPIS) in London, a professional organisation, which records requests for information from vets.

• The annual report into pesticide poisoning of animals is compiled by the Wildlife Incident Investigation Scheme (WIIS) and records the number of reported poisoning incidents in the agricultural sector. The numbers (about 500 in the year 2000) are relatively small and only a small proportion (20) of these incidents are down to slug pellet poisoning. Of these most of the affected cases were dogs but there were also reports of foxs, feral pigeon, cat and badger. The report classifies the incidents according to how the poisonings were caused — approved use, misuse or abuse. As manufacturers claim that poisonings are caused by misuse, the figures are a useful indication of whether this is true or not. The 2000 report noted 12 cases of abuse (deliberate poisonings), 7 cases of misuse (careless storage, spillage etc) and only one case of poisoning through approved use. In this case a dog walking alongside the edge of a field consumed slug pellets that were applied in accordance with required regulations and was taken ill (though the dog later recovered after treatment). So, slug pellets can cause poisoning even when correctly applied — although at only one recorded case in a year it is hardly a great victory for the anti-slug pellet campaigner. On the other hand it is impossible to say whether these figures are an accurate representation of actual poisonings or not, and when you compare these agricultural figures to those provided below by the VPIS they do seem surprisingly low. This could be because few people report incidents to WIIS. WIIS itself admits that, "wild animals such as badgers and foxes, which are likely to find the pellets palatable, are equally at risk in such circumstances. Unfortunately the fact that they are likely to skulk in cover once affected will mean that they are less likely to be found and reported to the scheme."

• VPIS have recorded increased numbers of poisonings due to metaldehyde slug pellets over the last five years — 33 cases (4 fatalities) in 1996, rising to 96 cases (7 fatalities) in 2001 (though this is largely due to an increase in subscriber vets). In the year 2000, 136 cases out of a total 5203 incidents of poisoning were attributed to slug pellets. Over the past five years most of the reported fatalities have been dogs and cats but reported cases also include one hedgehog, one deer, a donkey and a horse. Whether these figures seem small probably depends on which corner you’re standing in, but as the VPIS point out they only record the number of enquiries from subscribing vets. This leaves out members of the public who do not report cases to vets, vets who aren’t registered with the London centre and vets who don’t call the London centre because they know about metaldehyde poisoning already and have no reason to call. This would probably suggest, although there is no way of really knowing, that the figures for slug pellet poisoning in Britain are substantially higher than the VPIS figures. I also asked VPIS whether they kept records of how the poisonings actually occurred. This is what they told me: "For canines the serious cases and those with fatal outcomes all were incidents where animals accessed the pellets from the packaging. Dogs, being the scavengers they are, tend to eat the whole thing — box and all. There are some cases on our files where smaller animals (including dogs) have had effects from eating pellets spread around plants." Whether the pellets were laid very liberally in these cases, and thus against manufacturers instructions, they couldn’t tell me.

• Methiocarb is an insecticide so it will also kill predator insects. So it is better to use metaldyhde.

• Slug pellets kill other slug predators such as birds and hedgehogs.

• Veterinary Poisons Information Service (VPIS) in London offers services to subscriber vets and does not answer general enquiries.