Our collapsing Bee Colonies: is neonicotinoid poisoning at fault?
Thursday, May 1, 2014
Neonicotinoids are the most widely used seed treatment in the world. Research indicates that stray dust may be harming bee colonies and some experts are starting to question their use. But even the beekeeping community is divided about what to do about it
by MARY BAXTER
The Michigan manufacturer who made the Derks' customized twin-row vacuum seed planter sent the large crate without notice, and it arrived at the family's Chesterville farm right in the middle of soybean planting last spring.
Marty Derks and his father, Gary, had bought the Monosem planter the summer before. Seeding efficiency, accuracy and speed are big reasons why the majority of corn acres in Ontario are now seeded with vacuum-plated planters, rather than finger pick-up systems that use moving parts to insert seeds into the planting disk. Gary and Marty looked forward to shaving their planting costs on their corn and soybean crops.
But the planter had already arrived, so the sudden appearance of the crate was a mystery – until the manufacturer called to explain it contained two dust deflector kits, one for each of the planter's two vacuums.
The deflectors were intended to divert the dust generated during planting. Studies in North America, Europe and here in Ontario have implicated stray dust coming from vacuum planters in neonicotinoid (neonic for short) poisoning of honeybees. The studies show seed treatments using neonics can "rub off" the seeds and contaminate the talc or graphite lubricant used to help seeds flow through the planters. The lubricant, in turn, is expelled high in the air in the dusty exhaust.
In Ontario, provincial and federal researchers linked this dust to several bee kills in 2012 and 2013. "When one of the dealership's head salesmen found out we had the bee issue up here, he wanted us to put the boxes on that they intended for their European use. But it never got to that," says 26-year-old Marty. Instead of pursuing mechanical ways to manage the dust, Europe had opted for a two-year ban on neonics, he explains.
With the deflector in place and using the specially designed lubricant by Bayer CropScience that the federal Pest Management Regulatory Agency (PMRA) now requires all farmers growing neonic-treated corn and soybeans in Canada to use, Marty hopes he will become part of the solution when it comes to reducing honey bees' exposure to the pesticide class.
But even as Ontario's cash crop farmers tame the planter dust problem, concerns persist about the potential of chronic environmental impact. Debate about their validity and significance is contentious, divisive and highly political. The issue is also proving fertile ground for innovations that have the potential to shape how both grain farmers and beekeepers approach their business.
When neonics were first developed more than two decades ago, the agriculture industry heralded them as a significant advance from the chemicals they replaced, such as organophosphate and carbamate. This class of compounds was far safer to handle than its predecessors. More environmentally friendly, too, with initial studies showing little effect on humans and mammals (one type of neonic is the main ingredient in a flea and tick treatment for pets).
Neonics are derived from naturally occurring chemicals found in plants like tobacco, tomatoes and potatoes. The compound class is a neurotoxin that, in high doses, paralyzes and kills insects. Farmers have used it in the United States since 1994, with the first registration here in Canada as a seed treatment in 2003. The class is used on many different crops and has become the most widely used insecticide type in the world.
John Purdy, a retired biochemist and now a hobby beekeeper in Campbellville, was closely involved in the ecological research that supported the registration of Syngenta's Canadian neonic seed treatment products. One of the advantages that he found was what's considered to be a very short half-life in soil – in the range of 40 days. (A half-life describes the time it takes for a chemical to break down and become half of its concentration.)
"But there was a complexity to that," he says. As the chemical ages, it becomes less bio-available to the microbes that degrade it. It might be harder for the microbes to get at or there may be fewer microbes around that can degrade it. Or it might become "bound up" or absorbed by organisms that can't break it down but don't experience toxic effects from its presence. And that means a soil test conducted after that 40-day period may well reveal its presence, "but it would be biologically irrelevant," he notes. Researchers have since proposed that persistence of neonics in the environment, one of the areas of contention, might be anywhere from three to 16 years.
Cost-effective treatment
As a seed treatment, neonics are intended to protect the germination and emergence of corn and soybean crops from pests such as wireworm and slugs. The treatment is described as cost-effective compared to spraying. Stephen Denys, vice-president of sales and marketing at Pride Seeds and past president of the Canadian Seed Trade Association, estimates it costs $6 per acre for corn seed treatment and $12 to $14 per acre for soybean seed treatment because of the higher seed populations used.
Compare those costs to the $38 per acre he used to spend to foliar spray his Chatham-Kent farm's white bean crop twice before he started using a seed treatment.
The precision of applying the treatment directly to the seed is also viewed as less of an environmental impact compared to spraying. Compared to using an in-furrow or foliar application over an entire field, "there is a tremendous reduction in the amount of active ingredient being used," says Pierre Petelle, vice-president, chemistry, at CropLife Canada, the organization that represents the country's agricultural biotechnology industry. "When you compare to the alternatives of what we were using just 10 years ago, the reduction is significant in the amount of product that is actually needed to control those pests."
So it comes as no surprise that, by 2012, when some Ontario beekeepers began reporting unusual bee deaths, nearly all the corn seed that went into the province's ground received the treatment, as did roughly half of the soybean seed.
April 2012 started out warm and dry, and by May 5, most of the province's corn crop had been planted. In Lambton County near Watford, Dan Davidson, a commercial beekeeper who is currently president of the Ontario Beekeepers Association, anticipated a good year, as did many other beekeepers in the province.
In Canada, winter bee losses of between five and 15 per cent are considered fairly normal. Bee colonies are typically at their lowest numbers at the end of winter but build their population rapidly in the spring, when the queen starts laying eggs for new bees. (A queen bee can produce 1,000 to 1,500 new workers a day and colonies reach a population high of around 40,000 to 50,000 worker bees as nectar becomes available.) That spring, Ontario's overwintering loss for honey bees was 12 per cent, the lowest percentage in six years.
Nevertheless, Davidson was worried about his bees' health. From the United States and Europe had come reports of a strange phenomenon termed colony collapse disorder, where the beehive's worker bees would suddenly disappear.
One of the biggest concerns, though, had to do with varroa mites, a pest capable of piercing through a bee's tough armour and transmitting viruses, such as deformed wing virus. Nosema infection during the crucial winter months was another worry, as was American foulbrood, another disease.
One beautiful spring day, as Davidson was doing the rounds of his 1,700 hives, he encountered a disturbing sight. "Bees were crawling out of the hive twitching and dying like you see after you spray a wasps' nest," at one of the yards, he recalls. "They were falling onto the ground." With the help of provincial officials, he sent the dead bees to the PMRA for testing. They tested positive for neonics.
That spring and summer, provincial and federal government researchers received reports of 240 kills at the yards of more than 40 beekeepers in southern Ontario. There were reports as well from Alberta, Manitoba, Saskatchewan, Nova Scotia and Quebec. Some reports were attributed to spray drift. In June, the PMRA announced plans to re-evaluate the risk of several types of neonics in light of potential risk to pollinators. The agency cited reviews undertaken by other countries as motivation for its review, rather than the Canadian incidents.
Traces of neonics
The kills occurred again in 2013, as well as odd disappearances of foraging bees, and by the fall the PMRA had released a report indicating 75 per cent of the dead bees it sampled had detectable residues of neonics. It also found traces of two neonic chemicals used to treat seeds, clothianidin and thiamethoxam, in 90 per cent of comb pollen from the bee yards where the incidents had occurred, as well as in some water, soil and comb honey samples.
In a position statement published on its website, the Ontario Beekeepers Association called for a provincial ban on all neonic "conditional registrations until we understand how to manage the risks posed by these products to honey bees and other pollinators." Davidson says the request for a ban only covers use of the neonics in field crops.
By late 2013, however, Ontario's researchers and pesticide management companies were already well on their way to identifying the contributors to the bee kills and determining solutions. Art Schaafsma, a University of Guelph Ridgetown campus professor who specializes in field crop pest management, and Tracey Baute, Ontario's field crop entomologist specialist, led the studies.
Matching nine southwestern Ontario farms with nearby bee yards, they looked at the foraging activities of honey bees around corn fields during planting and evaluated the dust in the area where neonic-treated corn seed is planted, comparing standard lubricants such as talc or graphite with a new lubricant developed by Bayer. (Bayer also produces a neonic seed treatment.)
Some findings surprised them. For instance, they discovered bees preferred pollen from the trees and shrubs near the study sites over that from ground vegetation, initially thought to be a preferred choice.
The researchers also confirmed that the dust which planters emitted rose high enough to be caught up in the boundary layer of winds. That meant it moved out of the fields whether or not it was windy, and had a high risk of settling in the trees that the bees preferred. It also meant that the dust travelled far beyond where researchers were measuring "so we don't have answers on how it's settling out," Schaafsma told a lecture theatre jammed with farmers during the Southwest Agricultural Conference at Ridgetown in January.
Two of the Ontario yards indicated high neonic counts, and deaths there subsequently tested positive for neonic exposure. Other than that, it was very difficult to show a relationship between the level of neonics found in either the bees or the pollen and the mortality rate, although neonics were found in all the samples. "We don't know what that means just yet," Schaafsma says.
The researchers also looked at persistence of neonics in soil and found its half-life to be less than a year. Schaafsma explains that this means the risk of having the chemical build up in the soil is "quite low" – with the caveat that, as soil dries in the spring, moisture moves up through it and appears to be bringing residue, resulting in an accumulation of neonics in the layer of dry soil.
Samples of moving and standing water in or near the fields were also taken and analyzed. The highest reading was 40 parts per billion. Most samples registered less than 10 parts per billion. Higher rates were found in fields where replanting took place or a higher rate of neonic was used to treat an infestation.
The studies were funded by the Ontario Ministry of Agriculture, the University of Guelph, Agriculture and Agri-Food Canada, Grain Farmers of Ontario and the North American-wide Corn Dust Consortium, a group that includes bee, corn and seed industry organizations, Bayer, Syngenta and the University of Maryland. The Ontario results mirrored findings of Consortium-sponsored studies in Ohio and Iowa, but only the Ontario study tested Bayer's lubricant. The study concluded the lubricant reduced the amount of neonics escaping in dust by 28 per cent.
Further studies are scheduled to take place this year. Nevertheless, few now question whether planter dust containing neonics can cause bee kills. Whether planter dust poisonings is the only problem is the question that remains.
Dying queens
Chris and Christy Hiemstra are commercial beekeepers near Aylmer who raise and sell beehives to other operators. Last year, they sold nearly 1,600 hives.
They, like Davidson, have encountered mass bee deaths in their operation. Another problem has also emerged: their queen bees no longer last as long as they should. "The queen is supposed to live for about three years," Hiemstra explains. Instead, in the middle of summer, at a time when the hive is at its peak of activity, queens are dying and replacements have to be found. "We're all scratching our heads," he says.
There is evidence that insects exposed to neonics at sub-lethal levels can experience problems, including disorientation that may affect the bee's ability to find its way home, impaired foraging and slower colony growth, as well as a reduction in the number of queens it produces. Many of these studies have been challenged because they took place in labs and used far higher exposures to the chemical than those bees would experience in the environment.
The risk of neonic exposure from other avenues, such as through plant pollen and nectar, is another concern. Initial findings from an industry-financed study led by University of Guelph environmental sciences professor Cynthia Scott-Dupree, however, indicate these types of exposures have little impact on hive health, says Petelle. The study, conducted last year to satisfy requirements for a U.S. Environmental Protection Agency review of neonics as well as the PMRA review, explored how much neonic residue is left in the pollen and nectar of seed-treated canola, "which is a much more attractive crop to bees (than corn), and which is shown to have higher concentrations in the nectar and pollen than corn would ever have," he says. The rates detected in the plants' nectar and pollen "are far below levels which would impact bees, which is what the studies that our members have conducted have also shown," he says.
Nevertheless, researchers such as Peter Kevan, a University of Guelph professor emeritus who was one of the organizers of the Canadian pollination research initiative, notes enough research raises the possibility of chronic impacts to honey bees and possibly other pollinators to warrant further study. He also emphasizes the importance of considering a study's design when weighing its conclusions.
The Australian Pesticides and Veterinary Medicines Authority made a similar observation in its review of neonicotinoid use and the health of honey bees published in February. While tests "to study the lethal effects of pesticides on bees are well-defined and have been adopted into regulatory guidelines," the authority's report says, "studies related to sub-lethal effects are less well-defined and developed, and have generally not been incorporated into regulatory risk assessment schemes to date." (The authority ultimately concluded the use of neonics in agriculture had reduced the environmental risk of insecticide applications and, other than keeping a close eye on new research, any risks the compound class posed could be managed through regulatory, industry stewardship and educational steps.)
It's these kinds of concerns that have motivated the Ontario Beekeepers to call for a ban. But industry observers, such as Schaafsma, note that the Ontario group's action has divided the provincial, western and national industry organizations.
"I don't necessarily believe it's a split," says the Canadian Honey Council's executive director, Rod Scarlett. But he does acknowledge there may be some difference over "the most effective way to ensure the continued operations of beekeepers in southern Ontario." The national organization has proposed beekeepers work with farmers and other industry representatives to minimize the risks, and western beekeepers, who own the majority of Canada's honey bees, have not experienced the same problem, even though the seed treatment is also used on canola crops.
In Ontario, some beekeepers are uncomfortable with their provincial organization's stand and, earlier this year, several commercial beekeepers formed the Independent Commercial Beekeepers' Club-Ontario, a new organization that focuses squarely on the business of beekeeping. Twenty beekeepers attended its inaugural meeting in March, according to Hugh Simpson, a Grey County beekeeper with 300 hives and one of the new group's organizers. He estimates the group represents about 10,000 of the province's roughly 80,000 beehives.
Simpson, a former Ontario Beekeepers board member, says the provincial association's decision to push for a ban and ally with the Sierra Club Canada, an environmental organization, underlined how different are the interests of commercial beekeepers from the beekeeper hobbyists who form a large proportion of the Ontario Beekeepers' 3,000 members.
Davidson denies there is an alliance between the Beekeepers and the Sierra Club.
The members of the new club are making the statement that they are part of the agriculture community, Simpson says. "We are farmers with a different livestock and work with other farmers, and we understand the necessity for the responsible use of approved products. We want to work together to make sure we're all successful."
The issue is also motivating Grain Farmers of Ontario to push for change at the federal regulatory level. During a January presentation to the federal Standing Senate Committee on Agriculture and Forestry, which is currently probing bee health and bees' role in Canadian food production, John Cowan, Grain Farmers' vice president, called for "a formal process" for farmers and other non-registrant stakeholders to discuss sustainable agriculture practices with the PMRA.
When the PMRA released its notice of intent last fall to make a series of requirements regarding the use and handling of neonic seed treatments, "we found ourselves in new territory," he explained. The notice required the industry to justify its "continued need for neonicotinoid treatment on up to 100 per cent of the corn seed and 50 per cent of the soybean seed," and the Agency plans to release its assessment of the value of treated seed this year. During his presentation, Cowan said that preliminary results from a Conference Board of Canada study Grain Farmers had commissioned indicated a ban would result in yield loss for farmers and added costs for managing insects.
Small and medium-sized farms would be worst hit, he said. The impact could have a "trickle-down" effect on other government programs. "Bans on tech without equivalent replacement would put farmers on an uncompetitive position globally."
Troubling questions
But where is the third-party evidence that prophylactic use of the seed treatment is essential? The question puzzled Christian Krupke, an entomologist at Purdue University in Indiana.
Krupke had previously searched for ways in which bees could be exposed to planter dust contaminated with neonics following reports of bee kills in his state. He knew heavy wireworm infestations took their toll and neonics are a "good fit" for control. But he also knew such infestations were rare. A search for one for a recent study drove that point home. "We had to drive three and a half hours to find a site that was a maybe; we never did get a really good hit," he says.
Other questions troubled him. Wouldn't genetic engineering already provide significant control against some of these pests? How effective could a treatment be when, by the time the pests show up, there was a good chance the insecticide rates in the plant tissues are too low to do anything?
"The oldest trick in the book when you're marketing something is to take the approach that any of this laundry list of bad things could happen and then use that as a springboard to say, ‘well this product can guard against some of those things,'" he says. "But there's no evidence behind it."
So Krupke began studying the treatment's effectiveness not just on yield, but also on overall corn plant health, measuring properties such as damage at roots, stand count at emergence and plant height at different development stages. He hasn't found any statistical benefits from using seed treatments.
Nearly six years ago, an Ontario study headed by Schaafsma, which evaluated seed treatments' impact on corn during stressful growing conditions but without severe pest pressure, arrived at similar conclusions, noting that in those situations the treatment "was not warranted." A 2005 study by the provincial government that looked at the impact of a neonic seed treatment on corn under stressful conditions did find a yield boost for earlier planting dates, but otherwise noted a "negligible" impact.
There is a need for more research to support the prophylactic use of neonicotinoid seed treatments, acknowledges Petelle. "We feel that is an area that academia and government could do more, and we would be happy to partner with them on projects like that."
Derrick Rozdeba, integrated communications manager for Bayer, however, says studies "garnered through our seed partners" show a six to 14 bushel per acre corn yield increase through using the treatment. He adds that preliminary results from a study focusing on the economic benefits of corn and soybean treatments in North America will be published this spring "with a scientific peer review process." The study is being sponsored by Bayer, Syngenta and Valent BioSciences Corporation.
"I'm rather horrified to hear" Krupke's assertion of a marketing ploy, he says. "We're a science-based company." Products go through a "rigorous" approval process to obtain registration by the PMRA or the U.S. Environmental Protection Agency, a process that can take 10 years.
Paul Hoekstra, regulatory and science stewardship manager at Syngenta, also points to the rigorousness of Canada's regulatory controls as well as to research that has been done, in particular by Agriculture and Agri-Food Canada in Saskatchewan with canola, as well as by others at the University of Guelph that show the benefits of the seed treatments. Their work is showing it not only improves yield but also helps with plant competition by helping crops better manage physical stress such as cold soil or drought, he says. Hoekstra says he has not seen Krupke's research or the other Ontario studies but notes research he has seen that reaches a similar conclusion has typically been conducted on small plots. In larger-scale research, "you do see quite a significant benefit to yield," he asserts.
Hoekstra also points out that the product his company makes is sold to seed companies, which "aren't going to purchase a product that they don't see value in." Moreover, "the value of seed-applied insecticides has been clearly demonstrated by the uptake of this technology by the Canadian farmer," who has "embraced this technology."
In its best management practices released in January, the PMRA urges farmers to adopt a cautious approach to applying neonic seed treatments. Practice Integrated Pest Management (IPM), an approach that proposes adopting a variety of methods to manage pest pressure and minimize the impact on the environment, it advises. Determine if soil pests "are present at threshold levels or if fields have a high pest risk before making a decision to use treated seed."
Ontario researchers and agriculture ministry specialists estimate that only 10 to 20 per cent of the province's fields are at risk from wireworm and grubs. Among the risk factors: sandy soils and fields with a history of wireworm, cutworm, European chafer or other white grubs.
"Everybody that uses pesticides should use IPM. That only makes sense," says Ontario Beekeepers' Davidson. Randy Oliver, a biologist and beekeeper in California who publishes a popular science-based blog on beekeeping also gives the PMRA's approach a thumbs-up. Asking for evidence that prophylactic treatment is necessary is just good science and "a level-headed response to this issue," he says. "Treating all your seeds with pesticide is contrary to all the principles of IPM and in most cases it's probably unnecessary."
Petelle asserts the seed treatment is a form of IPM that provides an alternative to genetically modified crops such as Bt corn: "Part of the idea here is, yes, you have protection from the genetic modification but that's just relying on one mode of action. So by also having an insecticide seed treatment, you're providing an ability to protect that against those soil insects using two different modes of action."
And grain farmers are not convinced targeted use of treated seed is realistic. Denys says that, on his farm in Chatham-Kent, he will have sections where he needs the seed treatment and others where he won't. But how do you identify which acres to put the treated seed into?
"Part of the issue with IPM today is we don't necessarily have the tools to really forecast where we see an insect issue is going to happen and where it's not," he says.
Baute says the ministry does have scouting recommendations, techniques and thresholds. "In the next few years, we do plan to do a pest survey in conjunction with strip trials that we want to conduct through the Ontario Soil and Crop Improvement Association and come up with a high-risk map of where these pests are," to provide growers an alternative to prophylactic treatment. In the meantime, re-educating growers about what the pests are and their risks is a top priority for the provincial crop specialists.
She acknowledges there are many other hurdles to introducing forecasting as a preventative tool. Farming has changed and farmers no longer have the luxury of time to scout thoroughly.
Making it mandatory for growers to consult crop consultants before buying neonic-treated seed was one of the many recommendations in the Ontario Bee Health Working Group's final report released in March.
Denys, a member of the Working Group, says such an approach would add expense for the farmer and present other hurdles. "There would likely have to be some accreditation for that in terms of crop insurance, because who assumes liability?" he asks.
Then there is the question of how to issue the forecast data to farmers at the time they need it the most – in the late fall, when many place seed orders for the next year. Increasing the range of seed choices available would also be necessary. "I have growers who have said, ‘I know I have not had pests; I've often not wanted to use these but never had a choice,'" Baute says.
Regardless of the bee problem, there is benefit to looking at alternative methods of controlling some of the pests that neonics target. She explains that neonics stun but do not necessarily kill wireworms or grubs and, although the crop is protected, the population in the field is not lowered. There is value in rethinking the approach and "potentially even moving towards alternatives which we can rotate occasionally into, so we are managing the population again.
"The biggest problem with this issue is so many things are developing so rapidly. Everybody wants the solutions immediately. It does take time to reassess all those scenarios and put them in play."
In the meantime, as grain farmers prepare for a busy planting season ahead, preventing acute bee poisonings from stray planter dust remains the primary concern. It's crucial to follow the PMRA's best management practices, Schaafsma warned at the Ridgetown conference in January. If the rate of bee kills remains the same as last year's, he says, "you guys are done." BF