Guest blog – Are neonicotinoid pesticides responsible for the demise of bees and other wildlife? – by Rosemary Mason and Derek Thomas
Dr Rosemary Mason and Dr Derek Thomas are long-standing environmentalists
One of us has just returned from Orkney, where for the first time, we found the rare great yellow bumble bee (Bombus distinguendus), now restricted to Northern Scotland and the offshore islands. She was leisurely foraging on red clover and garden knapweed on a track at the edge of Kirkwall, the biggest town on Mainland.
I had been to Orkney some 25 years before to see the hen harriers. They had been studied by Eddie Balfour until his death in 1974 and later described by Donald Watson in ‘The Hen Harrier’, his impressive monograph about this iconic bird published in1977. However, over the last 20 years or so, the massive decline in invertebrates (animals without backbones) is a much more terrifying prospect than loss of a single rare species. Of course, many people don’t care much about invertebrates and would say “so what?” But all higher species (including humans) are completely dependent on them. Birds, amphibians and bats feed on insects, most crops depend on their pollination services and microbes recycle nutrients in soil and aquatic ecosystems.
What is most worrying is that many modern scientists seem to have little understanding of the environment. In 2006 the Government closed almost all of the Wildlife Research Stations, made 200 field scientists redundant and transferred the money into universities where it could be used for “hard” science; computer-driven population ecology and statistics. It is no longer fashionable to look at the environment. However, you don’t need science to show the declines in insects; twenty-five years ago if you went on a 300-mile journey in the UK, you would probably have to stop to clean the windscreen and headlights at least once. In June 2004, using a “splatometer” on their vehicle number plates, 40,000 drivers recorded an average of one squashed insect every 5 miles.
In 1991, Bayer CropScience introduced a new type of insecticide into the US; imidacloprid, the first member of a group now known as the neonicotinoids. Bayer Scientist Abbink certified that: “imidacloprid is the first highly effective insecticide whose mode of action has been found to derive from almost complete and virtually irreversible blockage of post synaptic nicotinic acetylcholine receptors (nAChRs) in the central nervous system (CNS) of insects.” Imidacloprid differed from conventional spray pesticides in that it could be used as seed dressings or soil treatments. When used as a seed dressing the insecticide will migrate from the stem to the leaf tips, and eventually into the flowers and pollen. Bees, bumblebees, hoverflies and butterflies that collect contaminated pollen or nectar from the crop will ingest a small dose of the toxin, but any insect that feeds on the crop will eventually die. The neonicotinoids were introduced into an environment that had already been affected by many toxic chemicals, some of which were persistent in the soil. In 1994 imidacloprid was licensed for use in Europe. In July 1994 beekeepers in France noticed something unexpected. Over the course of a few days, just after the sunflowers had bloomed, a substantial number of their hives would collapse, as the worker bees flew off and never returned, leaving the queen and immature workers to die. The French beekeepers soon believed they knew the reason; a brand-new insecticide called Gaucho® with imidacloprid as active ingredient was being applied to sunflowers for the first time. It took the French beekeepers nearly 10 years get bans on imidacloprid on sunflowers and maize, and for fipronil on all crops. During this time the National Union of Beekeepers organised two mass demonstrations in Paris and their President, Henri Clement, survived a personal court action against him by Bayer (the charge was that he had defamed their products). He was able to defend himself by citing the 2003 findings of the Comité Scientifique et Technique that linked low doses of imidacloprid to the disorientation and disruption of foraging. The summary was clear: “The treatment of sunflowers is a significant risk to bees in several stages of life”.
British reaction compared with the French
In contrast to their French counterparts, the British Beekeepers Association (BBKA) had been receiving money from the pesticides industry for endorsing safe pesticides; they were therefore in denial about the neonicotinoids. A BBKA motion tabled by members in January 2011 forced them to stop receiving money, but in June 2011 Tim Lovett was found to be featuring in a video promoting Bayer’s anti-varroal medicine as part of an EU symposium on Bee Health. A large group of beekeepers in the UK has now broken away and Phil Chandler has formed a separate organisation, http://www.friendsofthebees.org/
Dr Henk Tennekes, independent toxicologist
In November 2010, we discovered Dr Henk Tennekes’ new book: “Systemic Insecticides: a disaster in the making.” Dr Tennekes said that his book: “catalogues a tragedy of monumental proportions regarding the loss of invertebrates and subsequent losses of the insect-feeding (invertebrate-dependent) bird populations in all environments in the Netherlands. The disappearance can be related to agriculture in general, and to the neonicotinoid insecticide imidacloprid in particular, which is a major contaminant of Dutch surface water since 2004. The relationship exists because there are two crucial (and catastrophic) disadvantages of the neonicotinoid insecticides: the damage to the central nervous system of insects is virtually irreversible and cumulative. Tennekes showed that there is no safe level of exposure, and even minute quantities can have devastating effects in the long term. They leach into groundwater and contaminate surface water and persist in soil and water chronically exposing aquatic and terrestrial organisms to these insecticides. “So, what, in effect, is happening is that these insecticides are creating a toxic landscape, in which many beneficial organisms are killed off.” Tennekes and Sánchez-Bayo (Dr Francisco Sánchez-Bayo is an ecotoxicologist from Sydney) in a more recent paper demonstrated that chemicals that bind irreversibly to specific receptors (neonicotinoids, genotoxic carcinogens and some metals) will produce toxic effects in a time-dependent manner, no matter how low the level of exposure.
Mammals are being affected, not just pollinators
In 2000, researchers in an agricultural journal had shown that neonicotinoids acted on mammalian nAChRs as well, but it was considered that the selective nature of their binding (i.e. less affinity than in insects) made it safe for human exposure. There is now significant independent research to show that neonicotinoids have adverse effects on mammalian receptors and are having impacts on human health.
Massive exposure to the neonicotinoids of a global public that is totally unaware
In England, for example, in 2010, about one third of arable land was treated with neonicotinoid insecticides out of a total cropped acreage of about 9.9 million acres. Some fields had up to four applications of various pesticides. In Scotland in 2010 clothianidin was used on all crops in an area of about 25,000 acres, and thiamethoxam on an area of about 47,000 acres. In the US in 2010, 88 million acres of maize, 77 million acres of soya and 53 million acres of wheat were treated with neonicotinoid insecticides. However, in the UK, it is impossible to tell whether or not a field of rape, for example, has been grown from seeds coated with pesticides. In addition, they are used commercially as spray preparations on greenhouse-grown salad crops and vegetables, plant bulbs, and container-grown ornamental/house plant production for indoor and outdoor use and also pet products for fleas. There are at least four products for domestic garden use. Bayer Garden Products include Provado® Ultimate Bugkiller Concentrate (thiacloprid), Provado® Lawn Grub Killer (imidacloprid), Ultimate Bugkiller Ready to Use (thiacloprid) and Provado® Vine Weevil Killer (thiacloprid). They are used on golf courses, playing fields etc.
In 1991, the same year as the US EPA registered the first systemic neonicotinoid, imidacloprid, the US Geological Survey (USGS) implemented a National Water-Quality Assessment (NAWQA) Program “to develop long-term consistent and comparable information on streams, rivers, ground water, and aquatic systems in support of national, regional, State, and local information needs and decisions related to water-quality management and policy.”
In 2009, NAWQA published a Report: Pesticide Trends in Corn Belt Streams and Rivers (1996-2006). The USGS authors of the Report said: “The declines in pesticide concentrations closely followed the declines in their annual applications, indicating that reduced pesticide use is an effective and reliable strategy for reducing pesticides contamination in streams.” One of the first national studies on the presence of pesticides in ground water had been published in 2008. Laura Bexfield who conducted the data analysis said: “The results of this study are encouraging for the future state of the nation’s ground-water quality with respect to pesticides. Despite sustained use of many popular pesticides and the introduction of new ones, results did not indicate increasing detection rates or concentrations in shallow drinking water resources over the 10 years studied.” However, the 44 insecticides, pesticides and degradation products that NAWQA were measuring did not include the neonicotinoid insecticides or the herbicide, glyphosate. They are not measured in Europe or in the UK either.
Shift in pest management on crops worldwide
Over the last 20 years, the shift in worldwide pest management has moved away from reactive to prophylactic. Now many fungicides, pesticides and herbicides are applied to the seeds before sowing. Application of the chemical before pest damage has occurred often involves routine, calendar-based spraying and pre-emptive treatments. It is like humans taking permanent antibiotics. In the US where GM, herbicide tolerant crops are widespread, the phenomena of insect and herbicide resistance have locked US farmers into a pesticide treadmill. Target pests and weeds are capable of becoming resistant to the repeated use of a single insecticide or herbicide such that successively larger doses have to be applied. Farmers and weed scientists across the US heartland and cotton belt are now struggling to devise affordable and effective strategies to deal with the resistant weeds emerging in the wake of herbicide-tolerant crops.
What is the truth about the Varroa mite?
Pesticide companies and their supporters blame Varroa mite, or one of the many viruses that have been found in dead and dying bees, for Colony Collapse Disorder (CCD). However, infection with Varroa, or any of these pathogens, is a symptom, not a cause.
Immune suppression associated with the neonicotinoids
Three papers between 2009 and 2012 from Bee Researchers in France and the US show that the administration of tiny amounts of various systemic neonicotinoids (imidacloprid, thiacloprid) and fipronil, to Colony Collapse Disorder (CCD) bees was associated with a weakening of bee immunity, such that they became more susceptible to bee diseases. In fact, although Varroa mite had been identified earlier, it wasn’t until 1995 that it started killing bee colonies in the US. In 2006, full CCD was confirmed in the US, the same time as massive declines in bats were reported as a result of infection with a fungal pathogen, which causes White Nose Syndrome. This pathogen has wiped out whole bat colonies in many parts of the US.
Multiple calls for Defra, the US EPA and the EU to ban neonicotinoids
Many organisations worldwide have asked for a ban on neonicotinoids. Correspondence with European Commission Civil Servants, the US EPA, Defra, the UK Chemical Regulation Directorate and the Australian Pesticides and Veterinary Medicines Authority yielded almost identical responses; that there was no evidence that the neonicotinoid insecticides were harmful to bees. However, we found that all the registration documents said that they were highly toxic to honey bees and other pollinators and highly toxic to aquatic invertebrates.
Austrian Ombudsman Board calls for an investigation
On April 17th 2012 the EU Ombudsman opened an investigation into bee mortality and neonicotinoid insecticides following a complaint from the Austrian Ombudsman Board, alleging that the European Commission (EC) had failed to take into account new scientific evidence in favour of restricting the use of these insecticides as plant protection products. According to the Austrian Ombudsman Board, observations from beekeepers, as well as new scientific evidence, suggest that certain neonicotinoids have led to increased bee mortality in recent years. The EC asked the European Food Standards Authority (EFSA) Panel on Plant Protection Products to give a Scientific Opinion. In a Press Release on 1st June 2012, the EFSA conclusions were that for the research on bees and bumblebees, the concentrations used by the authors were too high to be “field realistic” and that the experiments should be repeated. However, the EFSA scientists, in their calculations, had failed to take into account evidence of contamination of water shown by New York State (NYS) Department of Environmental Conservation. This state (alone in the US) demanded monitoring because it is protective of the aquifers in Nassau and Suffolk Counties. As early as 1996 they had been concerned about the problem of persistence. In 2003, high levels of imidacloprid found in clusters of private wells down gradient of farms (one contained 6 ppb imidacloprid), at a golf course monitoring well and at monitoring wells near trees that had been treated with imidacloprid injection. As a result NYS never registered clothianidin and has severely restricted the use of imidacloprid and thiamethoxam. California Department of Pesticide Registration found residues of imidacloprid in treated plants in 2008 and Krupke et al. in a study of clothianidin and thiamethoxam in maize fields in 2012 found pesticide residues in soil, in dead bees, in wild flowers (dandelions), in pollen used to feed queens in the hive and in fields that had not be used for 2 years.
Henry et al. 2012 showed that nonlethal exposure of honey bees to thiamethoxam causes high mortality due to homing failure at levels that could put a colony at risk of collapse. Simulated exposure events on free-ranging foragers labelled with a radio-frequency identification tag suggest that homing is impaired by thiamethoxam intoxication. (On 29th June the French government has confirmed a ban on thiamethoxam-treated oilseed rape. They will be pressing ahead with a ban on Cruiser OSR, manufactured by Swiss agrochemical giant Syngenta, however, the ban only covers the Cruiser seed treatment, not Cruiser used for maize and rapeseed spraying.
Whitehorn et al. 2012 exposed colonies of the bumble bee Bombus terrestris in the laboratory to field-realistic levels of the neonicotinoid imidacloprid, and allowed them to develop naturally under field conditions. Treated colonies had a significantly reduced growth rate and suffered an 85% reduction in production of new queens compared with control colonies. Given the scale of use of neonicotinoids, the authors suggested that neonicotinoid insecticides may be having a considerable negative impact on wild bumble bee populations across the developed world. When exposed to these insecticides, only 15% of the mated queens survive the winter to start new colonies. This is already happening around the world. A reduction of 85% in the production of new queens accounts for the massive declines (and some extinctions) reported in the US and Canada from the late 1990s onwards.
In Regulation (EC) no 1107/2009 of the European Parliament concerning the placing of plant protection products on the market, Annex II, Criteria for approval, page 43, it states that a plant protection product should not be persistent in the environment. The persistence criterion is fulfilled where the half-life in soil is higher than 120 days. “Assessment of persistency in the environment shall be based on available half-life data collected under appropriate conditions, which shall be described by the applicant.” Registration documents confirm that imidacloprid, clothianidin (and presumably thiamethoxam which is broken down into clothianidin) are persistent in the environment and, according to EC laws, should never have been registered.
How can they be registered when scientists have reported all of these adverse effects? In the US and Europe, the Registration Divisions can over-rule scientists. They have a let-out clause in favour of economic factors and farmers. The recent analysis by the EFSA and sent to the European Commission rejected the findings of the new bee research. “The final decision on protection goals needs to be taken by risk managers. There is a trade-off between plant protection and protecting the ecosystem services, pollination, hive products and biodiversity. From a farmer’s point of view plant protection may be more important than hive products.”
It is evident that human health and the environment take second place to economics.
In the face of all this, why is it that major conservation NGOs are not demanding that neonicotinoids are banned on the basis of the precautionary principle.