Neonicotinoids - what are they, who uses them and should they be banned?
Neonics are insecticides - used to kill a variety of pests such as aphids (greenfly and blackfly) and root-feeding grubs. They act as a nerve poison on the insect, causing paralysis and eventual death.
They are systemic pesticides ie they are absorbed by the whole plant and transported to all its tissues (from root to flower) including the pollen and nectar. This affects bees and other pollinators, as well as worms in the soil, birds from eating the seeds, and aquatic life from the run-off into rivers and streams.
Why should we be worried?
Prof David Goulson, of Sussex University, writes
“The toxicity takes your breath away – just five maize seeds treated with neonicotinoids are enough to kill a grey partridge.”
Neonics are used on a vast scale by farmers worldwide. Virtually 100% of the corn in the US, Canada, Australia and China is treated. There are many different sorts of pesticides containing neonics, but in 2013 the EU imposed a moratorium on the use of just three; clothianidin, thiamethoxam and imidacloprid.
In the UK, much of the oilseed rape was treated with neonics to prevent flea beetle damage. It is usually applied by coating the seed before sowing. Unfortunately the sowing process often damages the coating, and releases a dust laden with poison. The toxin remains active in the plant as it grows, and stays in the soil for up to a year - often longer if there are repeat crop sowings year on year.
Here are some research papers which explore the effects of neonics on bees and other pollinators:
- On the ability of queen bumble bees to lay eggs
- The link between neonic poisoning and the decline in butterfly population in the UK.
- The first extensive and field-wide study, looking into the effects on a variety of bee species across the UK, Germany and Hungary. It shows a worrying inability for weakened bee colonies to overwinter, and the disastrous effects of neonics on queen bumble bees, and egg producing mason bees.
Gardeners also use neonics. Sometimes deliberately – as a rose spray to kill greenfly – and sometimes inadvertently. Many potted plants sold at garden centres have had their soil treated with neonics to prevent grub or weevil infestation. Even those sold as 'Bee Friendly'. See this research from Sussex University.
Neonics are also in nearly all bulbs and lawn treatments. They are used by commercial growers as sprays on apples, pears and a range of greenhouse crops. Cat and dog owners use them when treating their animals for fleas.
To ban or not to ban?
The major concern is for bees and other pollinators. Large scale treatment on agricultural crops is potentially devastating. An IUCN report highlights the “significant damage to a wide range of beneficial invertebrate species and is a key factor in the decline of bees.” The report argues that,
far from protecting food production, the use of neonics is threatening the very infrastructure which enables it.
The organic solution
There is absolutely no need for nicotinoids in our gardens or allotments. Garden Organic strongly opposes their use.
“Organic growing is based on the interdependencies of life forms,” says James Campbell, Chief Executive. “If we poison insects indiscriminately – including bees and butterflies - we risk poisoning other animals in land, air and water. It is, in the truest sense, not natural.”
Here are some tips for the organic grower to reduce aphid damage without using neonics:
- Encourage natural predators such as birds and parasitic wasps. Birds should be fed and watered during winter and have plenty of nesting areas. Parasitic wasps love cow parsley, dill and fennel flowers.
- Transplant seedlings in early summer, when they are strong enough to resist attack from aphids, which are at their peak in high summer.
- Do not over feed crops with nitrogen. This encourages green sappy growth loved by aphids.
- Use barriers such as fine netting to cover your crops. Install it immediately after planting out young seedlings, before the aphids have hatched in mid-summer. This prevents trapping them inside the netting.
- Use mulches ie light excluding materials, between plants (biodegradable plastic, straw, well-rotted manure or low growing green manures such as clovers). The latter two boost the soil’s reserves, and thereby reduces infections transmitted by aphids.
Here is the IUCN report outlining the global threat to biodiversity from the indiscriminate use of neonics. Matched by another damning report, which pulls together research papers produced by independent scientists worldwide ie those not sponsored by the agro-chemical industry.
Here is a video of John Atkin, COO of Syngenta, explaining why he thinks neonics are necessary.
DEFRA’s pollinator strategy was created in response to the outrage at the large scale use of neonics. They urge growers to create pollinator habitats adjacent to areas treated with insecticides. However, wild flowers and wild bees - as well as butterflies - are equally vulnerable to the poisons, as researchers at Stirling University found.
PAN (Pesticide Action Network) has produced a number of factsheets on bees and neonics, including one for farmers on how to grow crops effectively without poisonous insecticides.
And finally, this extensive review, produced by The Royal Society, highlights an interesting research conundrum. Because most research concentrates on honey bees, there is little evidence of the effect of neonics on other key pollinators such as hoverflies - or on worms, slugs, birds and aquatic life. However, the report explains that it is difficult and expensive to do field experiments – pollinators by their nature are wide ranging and variable in their habits. It is these vital gaps in our knowledge which lend more power to the persuasive proponents of neonics.