The following was written in 2007 as part of a two-part series in Bee Culture magazine coinciding with appearance of what was called at the time, Colony Collapse Disorder or CCD.
Remarks are provided here providing historical perspective.
Sanford, M.T. 2007 “Insecticides and CCD – Part I,” Bee Culture (June) Vol. 135 (6): 17-19.
Sanford, M.T. 2007 “Insecticides and CCD – Part II),” Bee Culture (July) Vol. 135 (7): 17-18.
With the recent flap about CCD, insecticides have inevitably been identified as one of the possible causes of larger-than-normal bee loss. The history of the relationship between beekeeping and insecticide application goes back a long way. In the 1950s it took some sleuthing to finally figure out that arsenic dust was being collected by bees in the field as pollen to both their and their colony’s detriment. Given the advantages of hindsight, who now could possibly argue that dusting with this extremely toxic substance does not affect honey bees. This even includes the active material in treated wood. Another situation arose with the use of microencapsulated pesticides in the 1970s, especially a product called PennCap-M®. The capsules acted like pollen grains and were a time bomb in colonies, because they could be brought back without harm to the forager, only became a problem when consumed by young bees in an effort to feed larvae.
Insecticides were such a problem to beekeepers in the late 1970s that congress authorized the beekeeper indemnity program, which provided payments to beekeepers from colonies lost to chemical application in both agricultural and urban (mosquito control) situations. However, this program became unwieldy because it was difficult to tell the difference between legitimate and falsely reported claims, and was finally discontinued.
This era brought into use the current information on the effects of pesticides on honey bees, pioneered by Dr. Larry Atkins at the University of California, Riverside for which most extension publications continue to draw their information. This was based on topical exposure to workers in small cages (LD50), however, there is evidence that bees may be exposed through other routes, including contaminated nectar, and that measurement of toxicity (LC50) might be significantly different. In Florida, this became a hot issue with a material called Temk® used in citrus groves. The active ingredient in this material, aldicarb, is a systemic insecticide and was thought to translocate into the blooms contaminating nectar. And although the active ingredient is certainly harmful to honey bees, there is evidence that the metabolites (break down products) of this material may even be more toxic than the parent substance.
U.S. beekeepers crossed the Rubicon of pesticide application when Varroa mites were introduced in the late 1980s. They literally “tore down the fence,” as one wag put it, quickly transforming themselves from anti-pesticide fundamentalists into willing pesticide applicators. Thus, beekeepers became much like those other agriculturalists that in the past they had reviled for “poisoning their bees,” the result of what one writer characterized as the “alchemy of greed.” This led to several potential effects, including contamination of the world’s beeswax supply via “biomagnification” of pesticides in the comb. Because of this, one large-scale beekeeper in Florida did away with all his natural comb and moved to plastic, which he believed would provide a reduced-pesticide environment for his bees.
The use of pesticides inside colonies to control Varroa mites inevitably brought more direct exposure to chemical pesticides. The candidates used to control Varroa mites on any scale also became more toxic as time went on. Treatments began with the rather benign fluvalinate, a synthetic pyrethroid, (Mavrik®) first soaked into wooden strips with an “emergency” Section 18 label, quickly replaced by a formulation on a plastic strip (Apistan®) with a broader use (Section 3) label. Beekeepers got 10 years use out of this material until mites became generally resistant due to lack of resistance management in many cases.
The next material to receive a label was called Bayer Bee Strips®, later formulated as CheckMite +®. The active ingredient is coumaphos in the class of pesticides known as organophosphates. When this material first became available, I wrote the following, “Coumaphos is in a class of highly toxic materials known as organophosphates (OPs). It is a cholinesterase inhibitor, which attacks the nervous system. Developments of this insecticide type were associated with German studies on related compounds, the so-called ‘nerve gases’ (sarin, soman and tabun). Suffice it to say OPs are among the most toxic of insecticides. The LD50 of coumaphos for absorption through the skin (dermal), for example, is 860 milligrams per kilogram of body weight in rats. It is, therefore, much less benign than fluvalinate, the active ingredient in Apistan®, a synthetic pyrethroid, with a dermal LD50 in rats of 20,000 milligrams per kilogram of body weight. Organophosphates are the basis of many commonly used insecticides (malathion, Diazinon®, parathion, Dibrom®).” In localized areas coumaphos resistance has already shown up in Varroa.
Another pesticide, amitraz, has an interesting history in Varroa control. Originally used off label by beekeepers, it finally got registered as Apivar®. However, it has been used so often that there is real risk that mites will have become tolerant of the parent material. See the referenced video using phone or tablet here.
This leaves beekeepers with no other hard pesticides at present that are as effective controls, the so-called “magic bullets” of Varroa mite control. Thus, so-called “soft” pesticides like formic and oxalic acids and essential oils (thymol based Apiguard® and Api-Life Var®) are being scrutinized. These, in combination with other techniques such as open bottom boards, drone trapping, the sugar shake and breeding (Russian bees and Varroa-sensitive hygienic stock), are leading the beekeeping community into a more integrated control technology for Varroa mites. However, even the soft chemicals can be hard on bees, and cannot be discounted when it comes to additive effects of chemicals on colonies already under stress by increased manipulation and management
The above discussion provided U.S. readers with an idea of the pesticide (chemical) load (influence) that has been put on honey bees over the last two decades since Varroa mites were introduced. In summary, although historically honey bees have been challenged by insecticides used in production agriculture and urban pest management (mosquito control), the ante was upped considerably when beekeepers began to employ them inside living colonies to control Varroa mites. It is no wonder that many are looking at this as at least contributory to colony collapse disorder or CCD.
In a way, the beekeeping experience has mirrored other production agriculture, which also continues to search for effective insecticides as more and more resistance by pests (insects) emerges. Fortunately a new tool has emerged that appears to have incredible promise. Predictably it is another class of pesticides, the neonicotinoids.
In a review of this subject, Motohiro Tomizawa and John E. Casida state, “The neonicotinoids are the most important new class of synthetic insecticides of the past three decades. Although related to nicotine in action, and partially in structure, the neonicotinoids originated instead from screening novel synthetic chemicals to discover a lead compound. Once optimized to imidacloprid (IMI) and analogs, the neonicotinoids joined the earlier chlorinated hydrocarbons, organophosphorus compounds, methylcarbamates, and pyrethroids to constitute the five principal types of active ingredients, all of which are neuroactive insecticides.
“Neonicotinoids are increasingly used for systemic control of plant-sucking insects, replacing the organophosphorus compounds and methylcarbamates, which have decreased effectiveness because of resistance or increased restrictions due to toxicological considerations. Neonicotinoids are also important in animal health care (i.e. flea control). These developments were possible because of the selective toxicity of the neonicotinoids, which is attributable to the specificity of insect and mammalian nicotinic receptors as reviewed here. Neonicotinoids are more toxic to aphids, leafhoppers, and other sensitive insects than to mammals. The physicochemical properties of the neonicotinoids played an important role in their development. The principal target pests are aphids, leafhoppers, whiteflies, and other sucking insects due to the excellent plant-mobile (systemic) property conferred by the moderate water solubility.”
“About 90% of the synthetic organic insecticides and acaricides, by market share, are nerve poisons acting on only four targets: acetylcholinesterase (AChE) for organophosphorus compounds and methylcarbamates, the voltage-dependent sodium ion channel for DDT and pyrethroids, nAChR for the botanical nicotine and most recently synthetic neonicotinoids, and the γ-aminobutyric acid (GABA)-gated chloride channel for polychlorocycloalkanes and fipronil. From 1987 to 1997, the use of compounds acting at the cholinergic nAChR shifted from sixth to third in overall ranking, in the most part replacing AChE inhibitors, and this trend is expected to continue.
“The long-term future of neonicotinoids will depend on continued evidence for the human and environmental safety of current compounds, including low toxicity to predators, parasites, and pollinators, no adverse environmental distribution, and fate. It will be enhanced by the discovery of new compounds with a broader spectrum of useful properties including control of lepidopterous larvae and pest strains resistant to earlier analogs. These biological features must be combined with suitable hydrophilicity for transport in plants, hydrophobicity for contact activity, and photostability for residual efficacy. Much has been learned about neonicotinoids in the first decade of their use and about the nicotinic receptor as a target for selective toxicity between insects and mammals. The benefits of neonicotinoids in crop protection and animal health can be enjoyed for many decades ahead with attention to their proper use in pest management systems that delay or circumvent the development of resistance in pest insects.”
Motohiro Tomizawa and John E. Casida. 2003 Selectivity Toxicity or Neonicotinoids Attributable to Specificity of Insect and Mammalian Nicotinic Receptors, Annual Review of Entomology, Vol. 48: 339-364
I have purposefully left intact the quotes above so readers can begin to understand some of the complexity of insecticides in general and neonicotinoids in specifics. Nevertheless, it is worth summarizing some of points made:
- The reference material for neonicotinoids is imidacloprid (many products will have this as the active ingredient).
- The benefits of the neonicotinoids include:
- A.High toxicity to insects (especially sucking insects like aphids, leafhoppers, fleas) and low toxicity to mammals (humans, dogs, cats)
B. Water solubility so that plants can use the materials in their vascular systems (systemic insecticides)
C. Different than other classes meaning insects will have to start over in developing resistance so they should be effective for a long period. - A 15% world market share and third ranking for the neonicotinoids by 2005 appears to be continuing”
Just how ubiquitous these products are becomes clear from one post to the Bee-L discussion list: “Imidacloprid is found in granules for controlling lawn grubs, liquid for tree and shrub pest control, and even in some potting soil mixes and fertilizers. Available at every Walmart in the country, I bet!”
In the southeast U.S, imidacloprid was truly a “miracle” substance for relief from one the region’s most irritating insects for humans and their pets. A pest control conference participant in a seminar confirmed for me that “flea jobs” had disappeared in the 1990s.
Because they are so specific for insects, however, means that honey bees could be readily affected by neonicotinoids. The first indication of this was in France, when beekeepers noticed an extreme decline in their colonies in sunflower fields. The Syndicat National d’Apiculture. Syndicat des Producteurs de Miel de France, and Union Nationale d’Apiculture Française issued a joint statement in Paris,18th. December 2000, which contained the following preamble:
“A press communication dated 16th. December 1998, produced by the Minister of Agriculture and Fisheries, announced that: The commission (Commission de toxiques) charged to evaluate the impact of Pesticides have studied the dossier ‘GAUCHO’ (Imidacloprid – BAYER). Following these studies, it has published the following advisory comment:
‘Taking into account recent studies evaluating the impact that Imidacloprid could have on the activity of bees when used as a seed treatment for sunflowers ‘, the Commission des Toxiques during its meeting held on the 16th. December 1998 considered that:
‘The examined data does not allow for a conclusion of indisputable effect of imidacloprid or its metabolites on bees and the production of honey.
“Inversely, it is not possible to totally exclude the effect of imidacloprid and its metabolites, taking into account the toxic effects of minute doses, doses that are in keeping with those concentrations potentially present in the plants during the period of harvest.
‘That complementary study should be undertaken to clarify the following points:
- The metabolism of the product in parts of the plant accessible to bees.
- The limit of the toxicity of the product and its metabolites for bees and the quantities present.
- The persistence of imidacloprid in the soil and the presence in crops that have not been treated.’” A demonstration in Paris by beekeepers associated with the above statement led to the pulling of the label for Gaucho®, the first and only time this has occurred to my knowledge.
Graham White in the United Kingdom at the time provided a rather complete synopsis of his analysis with many good references via the British Beekeepers Assocation Web Site:
“My concerns are: “As a beekeeper I am concerned that we are beginning to see evidence of unusual collapse of bee colonies in the UK.
“As a conservationist I am concerned that the large scale use of this highly toxic, systemic and persistent insecticide in the UK is effectively sterilising fields of all soil-invertebrate life including: earthworms, beetles, ladybirds, butterflies, moths etc. This has profound ecological implications, especially for insectivorous birds and mammals.
“Imidacloprid is highly persistent in the environment and is absorbed into all parts of the crop-plant: pollen, nectar and seeds. If collected by bees it is progressively concentrated in honey as the nectar is evaporated. It seems likely that it will be present in sunflower and rape-seed oil, – even if in small quantities. As a neuro-toxin this may have implications for the food chain and human health.”
He concludes: “Currently there is growing concern in the UK about the unexpected collapse of bee colonies in summer (a time when they normally thrive) and a sporadic incidence of failure of queen bees to mate or prosper. As yet the evidence is anecdotal and a national survey/ study is urgently needed but if the pattern follows that observed in Sweden, France and Canada, it seems a reasonable hypothesis that imidacloprid may be a causal factor. Imidacloprid is a systemic insecticide which attacks the nervous system of all invertebrates; the target pests are flea beetles and wireworms etc but beneficial species such as bees, earthworms and beetles are also killed. The pesticide is dusted onto seeds before they are planted and is used on a worldwide scale on crops including: sunflowers, oilseed rape, potatoes, wheat etc.”
Unfortunately, the evidence is mixed on imidacloprid’s presence in plants honey bees might use for forage. In one Canadian study:
“Kentville, N.S., March 8, 2002. A collaborative research project recently found that imidacloprid (Admire®) was not found in pollen and nectar of wild flowers and clover flowers in years following an in-furrow application of the product.
“The research project was undertaken as a result of a question raised by beekeepers whether imidacloprid or its plant metabolites was the cause of the dwindling bee populations reported by beekeepers in Prince Edward Island and other areas. Admire® is a popular insecticide for control of Colorado potato beetle and other insect pests in potatoes.
“Results of the Imidacloprid Residue Study were presented to the Canadian Honey Council and the Canadian Association of Professional Apiculturists in Banff on January 30, 2002.” The principal investigators were Jim Kemp and Dick Rogers.
They concluded: “Our answers to the question are based on determining the residue levels in parts per billion after imidacloprid was applied in-furrow. Measurements were taken in the current year and the first and second year after application. Imidacloprid and its two main metabolites (hydroxy and olefin forms) were not found in clover flowers and wildflowers, bee collected pollen and nectar, and uncapped honey. Residues can be measured when they are at or above the detectable limit of 2 parts per billion.”
“The study took place during the summer of 2001 in PEI and New Brunswick. It included sampling and analysis of over 3,800 soil cores, over 8,000 clover leaves, over 2,000 clover flowers, over 480 grams of wildflowers and over 6,000 honeybees.
“The Imidacloprid Residue Study was funded in part by the governments of Prince Edward Island and New Brunswick, with major funding by Bayer Inc. Additional partners and collaborators in the study included the Agriculture and Agri-Food Canada Research Branch, Cavendish Farms Research division, Jasper Wyman & Son and the potato growers and beekeepers of the Maritimes.”
A study by a team of French scientists “describes a new approach to assess more specifically the risk posed by systemic insecticides to honey bees with the example of imidacloprid (Gaucho®).
This approach is based on the new and existing chemical substances Directive in which levels of exposure (PEC, Predicted Exposure Concentration) and toxicity (PNEC, Predicted No Effect Concentration) are compared. PECs are determined for different categories of honey bees in relation to the amounts of contaminated pollen and nectar they might consume. PNECs are calculated from data on acute, chronic, and sublethal toxicities of imidacloprid to honey bees, to which selected assessment factors are applied. Results highlight a risk for all categories of honey bees, in particular for hive bees. These data are discussed in the light of field observations made on honey bee mortalities and disappearances. New perspectives are given to better determine the risk posed by systemic insecticides to honey bees”.
In their discussion, the authors conclude: “The PEC/PNEC derived from the calculation of honey bees’ exposure to which appropriate assessment factors were applied show that the risk posed by imidacloprid is alarming for all categories of honey bees. These ratios are all over 1, and greater in adult hive bees than in any other categories of bees. Whatever the validated toxicity data are, the determined PNECs are in a limited range of values (between 1.2 and 50 pg/bee). These estimates are in agreement with observations made in regions of extensive sunflower and maize cultures, which report a decrease in honey production since the launching of imidacloprid on sunflower plants in 1994.”
“At sublethal doses, pesticides are known to have profound impacts on the colony, in particular on the honey bees’ longevity, the brood production, the development of hypopharyngeal glands, and the egg laying . Imidacloprid is known to affect the honey bees’ cognitive behaviors such as the proboscis extension reflex PER. Learning and memorization in honey bees’ tasks are very important. For example, a forager that is disorientated might get lost and eventually die. In the case of massive foragers’ intoxications, the colony is likely to be greatly affected. In an experiment under tunnels, Vandame et al. exposed honey bees to deltamethrin at a sublethal dose that is 20-fold lower than the registered dose at which foragers are expected to be exposed to in the environment. They found that 54% of the treated bees were disoriented and took flight toward the sun. The authors concluded that such sublethal effects may be the cause of the symptom called the ‘disappearance bee disease’ by beekeepers who observed colonies’ weakening without finding dead bees close to the hives. This hypothesis was formerly raised by other scientists.”
Marie-Pierre Halm,, et. al. 2007. “New Risk Assessment Approach for Systemic Insecticides: The Case of Honey Bees and Imidacloprid (Gaucho),” Environ. Sci. Technol., 40 (7).
“Note that deltamethrin mentioned here is a pyrethroid5 in the same class as fluvalinate, considered one of the most benign pesticides used for Varroa control. If one mixes this knowledge with the fact that organophosphates (coumaphos in CheckMite+®) may also be used inside beehives at very low levels, then the blame for disorientation and forager loss may not lie strictly with the neonicotinoids. The bottom line is that we simply don’t know how much sublethal pesticide levels individual honey bees can take before their population becomes at risk of ‘disappearing’ and/or ‘collapsing.'”
Several beekeepers I have talked to are convinced that neonicotinoids are implicated in CCD. And David Hackenberg, one of the first beekeepers affected by the disorder, has written his pollination customers providing them a list of materials, asking them not to apply any of these substances, and to instead consider alternatives. Beekeepers might also consider this when planning their control measures for parasitic mites. There seems little question that adding any pesticide to the honey bee’s environment puts it and the colony it inhabits at greater peril.
A lot of this historical concern has not gone away. Neonicotinoids continue to be a flash point in the discussion of generalized potential effects not only on honey bees, but other insects as well. The following was published as a patreon post May 27, 2019:
Neonicotinoids are back in the news. Risks to bees are pretty much confirmed according to one report:
“Most uses of neonicotinoid pesticides represent a risk to wild bees and honeybees, according to assessments published by the European Food Safety Authority (EFSA) . The Authority has updated its risk assessments of three neonicotinoids – clothianidin, imidacloprid and thiamethoxam – that are currently subject to restrictions in the EU because of the threat they pose to bees. These new conclusions update those published in 2013, after which the European Commission imposed controls on use of the substances.
“For the new assessments, which this time cover wild bees – bumblebees and solitary bees – as well as honeybees, EFSA’s Pesticides Unit carried out an extensive data collection exercise, including a systematic literature review, to gather all the scientific evidence published since the previous evaluations. The team also applied the guidance document developed by EFSA specifically for the risk assessment of pesticides and bees. Jose Tarazona, Head of EFSA’s Pesticides Unit, said: “The availability of such a substantial amount of data as well as the guidance has enabled us to produce very detailed conclusions.
“There is variability in the conclusions, due to factors such as the bee species, the intended use of the pesticide and the route of exposure. Some low risks have been identified, but overall the risk to the three types of bees we have assessed is confirmed.”
Randy Oliver in the latest University of California, Division of Agriculture and Natural Resources UC Nursery and Floriculture Alliance Newsletter (Winter2018) concludes: “Everyone’s heard about the claim that honey bees are going extinct due to the neonicotinoid insecticides. Although I’m glad that folks are concerned about the bees, the fact is that that claim is not accurate.”
His “objective analysis” is more nuanced than the former release. He looks at two reasons the neonicotinoids are generally effective and less toxic. These include their more targeted use, being systemic, and the fact that their toxicity for many non-targeted organisms, including humans, is much less problematic than previous pesticides. These include the so-called “dirty dozen” persistent organic pollutants, which include some extremely highly toxic chemicals, many classed as organophosphates .
Unfortunately, these benefits come with major downsides, including extremely toxicity to insects in general and at the same time directly targeting those that interact with plants in a number of ways, particularly pollinators like honey bees.
Mr. Oliver concludes that neonics (abbreviation for “neonicotinoids”) are “ideally applied as seed treatments, where the amount per seed can be carefully controlled, so that by the time that a plant produces nectar and pollen, the residues are too diluted to harm pollinators. Unfortunately some serious incidents of inadvertent bee kills when the seed coating rubbed off in pneumatic seed planters occurred. Although this issue has now been resolved, according to Mr. Oliver, the question of neonic residues in nectar and pollen has not been resolved.
“In general, the residues in the nectar and pollen of properly-treated agricultural crops (typically less than 3 ppb) do not appear to cause significant adverse effects on honey bee colonies. I’ve personally visited beekeepers in corn, soy and canola growing areas, and they report that with the introduction of Bt genetically-engineered crops and the use of neonic seed treatments, that the pesticide issues that they suffered from in the 1960s and ‘70s have largely gone away.”
That said, he continues “ insecticides by definition are designed to kill insects. No insecticide is environmentally harmless, and as we learn more about unintended effects, our regulators must revise the approved allowable applications. We have now found that the honey bee colony is a special case, and it is able to ‘buffer’ the sublethal effects of the neonics on the colony. Despite clear adverse effects on individual workers, the net result to the colony is generally minimal.”
Unfortunately, he writes, “although properly-applied neonics appear to generally cause minimal measurable adverse effects on honey bee colonies, they may have more deleterious effects upon bumblebees and solitary native bees. This is a serious concern, of which the Environmental Protection Agency (EPA) is well aware. Another concern is that especially with the widespread prophylactic use of neonic seed treatment, more and more residues are ending up at agricultural field margins and in aquatic ecosystems.
“Certain uncultivated plants in the field margins concentrate neonic residues in their nectar and/or pollen. For example, a study in Saskatchewan found residues up to 20 ppb in some flowers — enough to start causing problems in bee hives (serious problems occur at 50 ppb), and strong adverse effects upon some native pollinators. These unintended effects upon native pollinators and aquatic invertebrates need to be addressed, and the universal use of treated seed should be restricted.”
Although agricultural deployment of neonics can be regulated, other uses such as nurseries and home-owners are more difficult to contend with. No insecticide is harmless, Mr. Oliver says, “All of agriculture should shift towards integrated pest management practices to reduce reliance upon pesticides. California is the most proactive state in the Nation as far as safe pesticide use. The ag community and chemical companies have gotten the message loud and clear that the consumer wants them to reduce pesticide use and develop more eco-friendly pesticides — both of which they are doing.” A recent release May 25, 2019 says the EPA has indeed now canceled registration for 12 neonicotinoids.
Finally, he says the best future will be the adoption of agroecology, which goes beyond “certified organic.” The field of agroecology is “based upon biology, soil improvement and sustainability, rather than arbitrary rules that exclude precision breeding and environmentally-friendly synthetic pesticides, fertilizers and practices. Keep in mind that it is the consumer who can affect the most rapid change — even the largest agribusinesses respond immediately to consumer demand.”
A report in the March 2018 Alberta Bee News about the Western College Veterinary Medicine (WCVM) program concludes that “bees need veterinarians too.” This group is also looking at the interface between agriculture and ecology, hoping to characterize the possible physiological effects that chemicals such as neonicotinoids might be having on honey bees. The health of of the bee population is “undeniably at risk,” the group reports, and it “may be that neonicotinoids” are partially to blame.
Bill Hesbach: “If one is interested in some perspective on past US alternatives to neonicotinoids, it’s worthwhile to get a copy of book Pollinator Protection by Johanson and Mayer.” Bill provided a URL to a copy of the out-of-print original book. Larry Conner at Wicwas re-issued the book so we could use it in our Journeyman Online Classes – it’s a required book. The text is by J and M, the tables giving LD and RT values for every pesticide tested up through the 90s includes the work of Larry Atkins. The new, reprint (still retains all of the original’s text, charts, tables – just has a new cover) is available.
“This book provides the history of pesticides in USA by the three people who were formative in terms of establishing the testing protocols used to this day by EPA and in terms of testing and ranking for hazard just about every pesticide used in the US during their careers. Unfortunately, Dan is the only one still with us. Louisa Hoovens, Ramish Sagili, Erik Johansen (Carl’s son) updated Larry’s data with information for the more recent pesticides in an Oregon State Extension Brochure, How to Reduce Bee Poisoning from Pesticides: OSU also makes this available as a Smart Phone App in iOs and Android versions.
“It’s free and every beekeeper and grower should have a copy. One note, the OSU Brochure/App updates the old Riverside Extension Brochures of Atkins – in a similar style and format. The Johansen and Mayer book provides the history, the background, explains testing protocols, and puts the information together in a readable manner that emphasizes application of their life-long experience into the context of protecting pollinators – not just pesticide toxicity and residue rankings but also basic information of apiary locations, pesticide drift, effects of weather, etc.
“Get the book and the brochure and you’ve got the ability to make the comparisons that have been requested. When we started our classes, the J&M book was out-of-press. Larry was able to find the original and re-print it. We get some comments about it being an old book. But it’s all based on testing for pesticide registration – the data and information never goes out of date. It has a dated look – all black and white, but it is what it is – a gold mine of information, all in one place. The good news is that we get reports of class members buying copies to give to their local bee associations, new beekeepers, and many give them to growers. This information is further referenced in an October 2018 article in Bee Culture magazine concerning the history of testing honey bees for pesticide toxicity.
There are the other effects of neonicotinoids we continue to learn about as noted in the abstracts of the Proceedings of the 2018 American Bee Research Conference: Honey bee food glands can be affected by neonicotinoids, Selina Bruckner, Lars Straub, Laura Villamar-Bouza, Peter Neumann, Geoffrey R. Williams. Department of Entomology and Plant Pathology, Auburn University, Auburn, AL, USA. Institute of Bee Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland. European Food Safety Authority, Parma, Italy. Swiss Bee Research Center, Agroscope, Bern, Switzerland.
“Hypopharyngeal glands (HPGs) of mature worker honey bees (Apis mellifera) are responsible for the production of royal jelly that is used to feed developing individuals. Neonicotinoids, systemic insecticides widely used for insect management, are suggested to negatively affect HPGs. However, it is unknown how timing of exposure affects HPG development. Based on previous literature, we hypothesized that field realistic concentrations of neonicotinoids would negatively affect HPGs, and that negative effects on individuals both developing (i.e., eggs, larvae, pupae) and residing (i.e., adults) during pesticide exposure would be strongest.
“To test our hypotheses, we employed a cross-foster experimental design. Fourteen queenright colonies were randomly allocated to either control or neonicotinoid treatment groups. For 49 days, a pollen paste was fed to the colonies used to rear experimental workers; the pollen paste fed to the neonicotinoid group was spiked with 4.9 ppb thiamethoxam and 2.1 ppb clothianidin. At adult emergence, half of the experimental workers from each colony were transferred to another colony within the same treatment (Control to Control or Neonicotinoid to Neonicotinoid), and half to another colony of the opposite treatment (Control to Neonicotinoid or Neonicotinoid to Control). Experimental workers were recaptured 8 days post-emergence, the typical age of nursing, for HPG examination (Figure 3).
“We found that size of HPGs was negatively affected by neonicotinoids. Moreover, individuals both developing and residing (Neonicotinoid/Neonicotinoid) under insecticide exposure exhibited the smallest HPGs. These data suggest that impaired HPG development due to exposure to field-realistic concentrations of neonicotinoids may be an important risk factor for honey bee health. Considering the importance of HPGs to colony development and queen health, pesticide risk assessment schemes should consider HPG quality in the future.”
It turns out, neonicotinoids are just one of the materials currently being examined within the context of both environmental impact, as well as effects on specific insects, such as the honey bee. The genetic literacy project looks at pesticides and honey bee losses in this context in some detail.
An ABJ Extra also looks at pesticides in general: Commercial Pesticides: Not as Safe as They Seem
“Lack of information on the effects of all pesticide ingredients makes them appear safer than they are — potentially causing serious harm to people and the environment. New regulations are needed to protect people and the environment from toxic pesticide ingredients that are not currently subject to safety assessments.
“This is the conclusion of the first comprehensive review of gaps in risk assessments for ‘adjuvants’ – ingredients added to pesticide formulations to enhance the function or application of the active ingredient.
“Ignoring the potential dangers of other ingredients in commonly used commercial pesticides leads to inaccuracies in the safety profile of the pesticide solution, as well as confusion in scientific literature on pesticide effects, finds the review published in Frontiers in Public Health.
” ‘Exposure to environmental levels of some of these adjuvant mixtures can affect non-target organisms — and even can cause chronic human disease,’ says Dr. Robin Mesnage from King’s College London, who co-wrote the review with Dr. Michael Antoniou. ‘Despite this, adjuvants are not currently subject to an acceptable daily intake and are not included in the health risk assessment of dietary exposures to pesticide residues.’ ”
“Pesticides are a mixture of chemicals made up of an active ingredient – the substance that kills or repels a pest – along with a mixture of other ingredients that help with the application or function of the active ingredient. These other ingredients are known as adjuvants, and include dyes, anti-foaming agents and surfactants.
“Regulatory tests for pesticide safety are currently only done on the active ingredient, which assumes the other ingredients have no effects. This means the full toxicity of a pesticide formulation — including those used in both agriculture and domestic gardens — is not shown.
“Currently, the health risk assessment of pesticides in the European Union and in the United States focuses almost exclusively on the active ingredient,” explains Dr. Mesnage. “Despite the known toxicity of adjuvants, they are regulated differently from active principles, with their toxic effects being generally ignored.”
Based on a review of current pesticide literature, the authors describe how unregulated chemicals present in commercial formulations of pesticides could provide a missing link between pesticide exposure and observed negative outcomes. The researchers focused on glyphosate-based herbicides, the most used pesticide worldwide.
They point out that this weed killer has so many different adjuvant formulations that a safety test of one weed killer does not test the safety of another. “Studies comparing the toxicity of commercial weed-killer formulations to that of glyphosate alone have shown that several formulations are up to 1,000 times more toxic than glyphosate on human cells.”
“We believe that the adjuvants are responsible for this additional toxic effect,” says Dr. Mesnage. The authors also highlight neonicotinoid insecticides — strongly suspected to be involved in the collapsing of bee colonies — as another example of adjuvant toxicity affecting non-target organisms. An adjuvant used in these insecticides to increase the penetration of the active ingredient has been shown to cause varying toxic effects in bees.
“On top of this, residues of the toxin have also been found in honey, pollen and beeswax produced by contaminated bees. The authors hope their review will stimulate discussion on the toxicity of commonly used pesticides and encourage more thorough regulations.
“Testing of whole pesticide formulations instead of just active ingredients alone would create a precautionary approach, ensuring that the guidance value for the pesticide is valid for the worst-case exposure scenario,” says Dr. Mesnage. Their findings have already had a considerable impact. The European Food Safety Authority is now reassessing the validity of pesticide risk assessment in the EU, and authors hope that this reassessment can extend to entire commercial formulations of pesticides and their other ingredients. Not the previous reference to the EFSA stance on neonicotinoids. Part of the problem in many of the conversations that currently exist concern asking the right question.
In conclusion, it seems that every discussion concludes that on some level are all pesticides bad for the environment? Perhaps, but another question needs to be answered as well. Should agriculture practice be abandoned in favor of no chemical inputs?
And then there’s the issue of honey bees as an “agricultural activity,” as opposed to their importance in conserving “biodiversity.” As a Bee Culture Catch the Buzz concludes: “Both wild and cultivated pollinators are afflicted by pesticides such as neonicotinoids, as well as other anthropogenic effects – from loss of hedgerows to climate change – which drive the much-publicized die-offs among farmed bees and the decline in wild pollinator species over the last few decades. Honey bees may be necessary for crop pollination, but beekeeping is an agrarian activity that should not be confused with wildlife conservation.”
The Risk Monger has his own take on the neonicotinoid debate calling it, a Failure in European Leadership
His conclusion: “After five years of writing on this, around two dozen blogs and several threatened lawsuits, I once again am feeling rather lonely in Brussels. For the second time in six months, I find myself apologising to European farmers even though I am not in any official channel representing them. People have a right to be furious.
“But I am not angry at the expedient cowards in official positions. I understand how the activists are biased to the point of feeling they can justify their lies and cherry-picking. I get that there are many under-employed and unappreciated scientists who were attracted to the attention and money from the NGO anti-pesticide community. I have long given up on the organic food industry lobby ever adopting or following an ethical code of conduct. I am not surprised by any of the bullshit these groups can claim responsibility for.
“What surprises and disappoints me is how the food manufacturing industry sat back and did nothing as the farmers who supply them got strangled by the naturopathic cult machinery. The big food companies depend on a reliable supply of agricultural yield to produce the food Europe is famous for and yet, to my knowledge, not one of them stuck their neck out to defend farmers and the tools they need. The word ‘neonicotinoid’ did not appear once on the FoodDrinkEurope website nor among their main members.
“Perhaps the food industry doesn’t think the plight of European farmers is important. If costs go up, so will their margins. If European farmers can no longer farm, will Nestlé and Danone simply import more food from another continent? Were they so afraid of how a small band of activist zealots might activate a twitter storm on their brand pages that they decided to step back and pretend that evidence did not matter? Would they rather sell unsustainable food than try to educate European consumers on the science behind reliable crop technologies? In their hunger for higher organic margins, are food manufacturers willing to see those less fortunate go hungry?
“These are the real cowards … and they’re disgraceful! As the European neonic saga closes, the real victim is leadership. Europe has made failure its objective, cowardice its political virtue and ignorance its culture. With the recent cancellations of 12 neonicotinioids on May 25, 2019 it now appears that the U.S. EPA is following the European example.
The latest information on this class of pesticides is produced by Dr. Scott McArt at Cornell University as noted on the YouTube program at insidethehive.tv.
For information on pesticides in general, see exotox.net
