Pets and Pesticides PDF Print E-mail

Dave Goulson, a trustee of PAN-UK and well known bumblebee biologist, tells us about the potential issue of the pesticides we put on our pets getting into the environemnt and poisoning bees, earthworms and other essential organisms in our ecological communities.

Every summer we have a family holiday in France, and every year we have to solve the problem of finding someone to look after our loveable mongrel dog, Poppy. Last year we opted for an eccentric lady who takes dogs into her own home when their owners are away; her place is full of animals, and rather whiffy, but we figured that Poppy would much prefer it to kennels, and we were correct. The only problem was that she came back with fleas, which prompted my wife to pop her in to the vets. They sold her some Advocate flea treatment, recommending a monthly prophylactic dose year in, year out. As someone with a professional interest in pesticides I looked at the small print on the packet to see what was in it, and was horrified to see that it is was a neonicotinoid insecticide, imidacloprid.

This neurotoxic chemical has been linked to bee declines around the world, and has also been implicated in declines of aquatic insects, insect-eating birds and farmland butterflies. It is toxic to insects at fantastically small doses, and can be highly persistent in the environment, lasting for years in the soil, and being sucked up by plant roots and contaminating their nectar and pollen. And we were dripping the stuff onto the family dog’s neck (as advised, the only place the dog cannot lick, but exactly where my children stroke her or sometimes cuddle her and press their face into the fur). The recommended dose for Poppy, a medium to large dog, is 250 mg every month. That does is enough to give a lethal dose (an LD50, a dose that kills 50%of test animals) to 60 million honeybees, or about 60 partridges. Of course neither bees nor partridges are likely to come and feed on my dog, but nonetheless this is a serious amount of neurotoxin to be being used by untrained pet owners in their homes. Where does it go? Neonicotinoids are water soluble, so presumably it washed off the next time your dog is out in the rain, or jumps in a stream or the garden pond. Do they also come out in the dog’s urine and faeces? We don’t know. Nobody does, because nobody has looked. There is, quite literally, not one single published scientific study on this subject.      


Veterinary practice managers often ask their vets to try to encourage any dog or cat owner who comes in to the surgery to buy a prophylactic flea treatment. Suppose they succeeded. Let’s do a quick back-of-an-envelope calculation. There are about 8.5 million dogs and 7.4 million cats in the UK. If all received the recommended dose that amounts to a staggering 32,604 kg of imidacloprid every year, more than is used in arable farming. It is enough to give a lethal dose to 8 x 1015 honeybees. To continue my spurious calculations, that is roughly enough to give 1000 times the lethal dose to every honeybee on Earth (and remember, this is just UK use of Advocate). Of course, this is all a bit silly. Not every dog or cat is treated by any means, and very little of that treatment is likely to end up anywhere near a bee, but it is very likely to end up coming into contact with earthworms, pondlife, dung beetles, flies and so on.

Many vets have heard of the bee crisis, have heard of neonicotinoids and the EU moratorium, and yet have no idea that Advocate contains a neonicotinoid. Most beekeepers and conservations are also unaware. This seems to me to be a story that needs to be told, and something that urgently needs scientific study. Where does all that neurotoxin go, and what does it harm?

Footnote: The most common alternative to Advocate is Frontline, which contains the active ingredient fipronil. This is not a neonicotinoid, but has many of the same properties and is probably no less dangerous to the environment.

Dave Goulson is currently fundraising to research which pesticdes are in 'bee friendly' plants sold in plant nursaries nationwide and if they are effecting our pollinators.  Find out more about the project here and pledge to help protect our pollinators!

sorry. Thanks, but this is a charity site and upgrading from 1.5 is not going to be straightforward when they have no web dev budget, have a heart!