Thursday, 18 April 2013

What, exactly, ARE neonicotinoid pesticides?

Neonicotinoids are a group of insecticides that include 'imidacloprid', 'clothianidin', 'thiamethoxam', 'thiacloprid' and 'fipronil'. They are neurotoxins (nerve poisons) that have been designed to attack the insect's central nervous system; causing paralysis and eventually death. Their target insects include vine weevils, aphids, whitefly, colorado potato beetle, termites and other sap sucking insects.  As well as causing paralysis and death, neonicotinoids also produce other chronic and sub-lethal symptoms, (both in target and non target insects) such as interfering with the insect's navigation systems and, crucially, impairing their ability to groom themselves

Neonicotinoids were introduced in the early nineties and are now the world's most widely used group of pesticides. They are used prophylactically instead of reactively, which is a little like us taking antibiotics throughout the year just in case we are exposed to someone with a chest infection in December.

They are water soluble and remain in the soil for many years. Their high persistency in soil and water results in a sustained exposure to these pesticides, not only to bees, but to other non-target organisms and pollinators, including aquatic invertebrates, moths, butterflies and hoverflies and (indirectly) bats, amphibians and insect eating birds.  

"Neonicotinoid insecticides act by causing virtually irreversible blockage of postsynaptic nicotinergic acetylcholine receptors (nAChRs) in the central nervous system of insects. The damage is cumulative, and with every exposure more receptors are blocked. In fact, there may not be a safe level of exposure." Dutch toxicologist, Henk Tennekes.

Which crops are treated with neonicotinoids?

Neonicotinoids are used as seed treatments or soil treatments on over 140 different crops including soy, corn, wheat, cotton, legumes, potatoes, sugar-beet, sunflowers, rapeseed and flax. Until last year, they were used on the 740,000 acres of Californian Almond Trees. One third of all arable land in the UK now grows crops treated with neonicotinoids.

Less well known is the fact that 'Fipronil' (also a neonicotinoid), is used in flea treatments for dogs and cats.

How do neonicotinoids differ from other pesticides?

Until the introduction of insecticides such as neonicotinoids we were able to see pesticides with our own eyes as they were being sprayed onto our crops. Neonicotinoids, and some other groups of modern pesticides, work in a very different way. They are applied as seed dressings or soil treatments, appearing invisible so that many people, including some farmers, are unaware that they are even using them. Instead of being used reactively (i.e. after a problem has been identified) they are used 'prophylactically' which means crops are treated as a matter of course to safeguard them against the possibility of an attack by the pesticide's target insect. This is like human beings taking antibiotics all year round to protect us from the possibility of succumbing to a sore throat or flu.

The biggest difference between neonicotinoids and all other pesticides is that neonicotinoids work  'systemically'.  This means that once the seed (or the soil in which the seed has been planted) has been coated/treated with the insecticide, that insecticide is then taken up through the entire plant via it's vascular system.  So, it ends up in the plant's roots, stem, leaves, flowers, fruit, sap (guttation), pollen and nectar.....and it - does - not - wash - off.

We are told by DEFRA that this is ok. It is, apparently, 'safe' for bees and other pollinators to forage on crops whose seeds have been treated with neonicotinoids because they only ingest the pesticide in sub-lethal doses i.e. 'doses not large enough to cause death'. This might be ok if each bee only visited one plant and took one dose of 'sub-lethal' pollen in it's life time - but this, of course, is not the case.

Interestingly, when neonicotinoids were licensed for use and passed as 'safe for bees', this was done without them ever being tested for sub-lethal or chronic effects on bees.

Why I have written this particular blog post: 

More and more people are now taking the time to write to supermarkets, DIY stores and garden centres to ask them to remove products that contain neonicotinoid pesticides from their shelves - and some are personally speaking to the managers in their local stores. However many are still not 100% sure exactly what neonicotinoids are or how they harm bees and other invertebrates.

It's good to be furnished with some facts when you speak to people who can influence policies, so I have written this short blog post to explain what they are

I'm sure there are better explanations out there, but in case you can't find one do please feel free to use this. It would great if you could also share this on twitter, facebook, forums and any other social networks you use.....the more people who understand what we're 
dealing with the better!

Please keep writing to your MPs asking them to pressurise our Secretary for the Environment, Mr Owen Paterson, to support the EC's proposed partial ban on neonicotinoids. You can use the wording on the Buglife website  HERE  to help you write your letter/email.

Please also ask your local supermarkets, DIY stores and garden centres to remove products containing these insecticides form their shelves. Especially Provado Ultimate Big Killer which, ironically and outrageously is currently being offered with 'free seeds for bees'!!!