Neonicotinoids and pollinator health - the evidence

Independent experts have continually advised government on the safety of neonicotinoid pesticides which are a key tool in UK food production. It is this scientific advice upon which the government has resisted calls to support a permanent ban from campaign groups who are often fundamentally opposed to the use of any pesticides in food production. It is vital that any decisions government takes regarding pesticides are based on sound science and the expert technical advice of the regulator rather than emotive public campaigns.


Calls for bans have often been made on the basis of the “precautionary principle”, claiming that the lack of evidence should mean we “play it safe” and stop using these insecticides because of a theoretical risk. However, this ignores the serious implications of such a ban. The most recent survey from the Agriculture and Horticulture Development Board (AHDB) found that 3.5% (equivalent to 22,000ha) of the winter oilseed rape planted in England had been lost to Cabbage Stem Flea Beetle following the 2013 moratorium.


There are a range of conflicting studies on the issue of neonicotinoids and pollinator health, including a recent study from Sweden published in Nature, “Seed coating with a neonicotinoid insecticide negatively affects wild bees” (Rundlöf et al). This found wild bee densities in neonicotinoid treated oilseed rape fields were around half of those in untreated fields. But it also found no negative impacts on honeybees. We feel more research should be carried out to understand why the findings were so at odds with previous studies.


In 2014, a body called the International Union for the Conservation of Nature (IUCN) Task Force on Systemic Pesticides (TFSP) published a study, subsequently widely referred to, claiming that neonicotinoids were causing “significant damage to a wide range of beneficial invertebrate species and are a key factor in the decline of bees.” These studies should be treated with a degree of caution in light of reports suggesting that the scientists had “decided in advance to seek evidence supporting a ban on the chemicals” (‘Scientists accused of plotting to get pesticides banned’, The Times, 17 December, 2014).


Other studies have found no harm to bees from neonicotinoids. As mentioned previously, the Rundlöf study from Sweden found no negative impacts on honeybees. A study by Cynthia Scott-Dupree (University of Guelph) and Chris Cutler (Dalhousie University) found that foraging on neonicotinoid seed-treated crops, under realistic conditions, poses low risk to honeybee colonies. The Neomehi Project in Finland also suggested neonicotinoids do not cause immediate harm to honeybees.


It is important that researchers continue to gather evidence on the impact of neonicotinoids so that a proportional and informed decision on their use can be made. The independent Centre for Ecology and Hydrology (CEH) has been commissioned by the government to conduct large scale field trials in the UK, Germany and Hungary monitoring the effects of neonicotinoids on bees. In addition, scientists will sample residues of neonicotinoids in the soil and plant tissue, nectar, pollen, wax and honey. These trials should provide policymakers and regulators with independent, high quality scientific evidence on which to base their decisions.

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