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Curtailing Honeybee Losses

Stakeholders seek to reduce the amount of pesticide-contaminated dust generated during corn planting

by Britt E. Erickson
March 25, 2013 | A version of this story appeared in Volume 91, Issue 12

Credit: Bayer CropScience
Bayer CropScience plans to field-test a seed lubricant system that reduces pesticide-laden dust generated from corn planters, such as the one shown here.
A tractor planting corn.
Credit: Bayer CropScience
Bayer CropScience plans to field-test a seed lubricant system that reduces pesticide-laden dust generated from corn planters, such as the one shown here.

The Midwest U.S. and parts of Canada experienced unusually high numbers of dying honeybees associated with last year’s corn planting. The culprit is believed to be contaminated dust, generated when seeds treated with neonicotinoid pesticides rub against each other inside planters that use air to enable uniform planting of seeds. Dust is released in the exhaust when seeds are expelled from the planter to the soil.

To combat the dust problem, the seed industry is developing new products and cleaning processes to better ensure that the pesticides, which protect germinating seeds from soil pests, adhere to seeds during planting. A group of stakeholders has also formed a collaboration to get a better handle on honey­bee foraging conditions around cornfields and to test a new lubricant for seeds that could reduce the amount of pesticide-laden dust emitted during corn planting.

Called the Corn Dust Research Consortium, the collaboration was formed last month by the pesticide industry, seed companies, farm equipment manufacturers, corn growers, beekeepers, conservation groups, and researchers from academia and the U.S. and Canadian governments.

Although exposure to pesticide-contaminated dust is just one of many factors contributing to honeybee losses, the pesticide industry and the new consortium hope that solving this one particular problem will help reduce the number of honeybee deaths.

Stakeholders involved in the consortium are optimistic that they will find a solution to the dust problem in time for the corn-planting season in April or May 2014. To do so, they have set an ambitious schedule for the rest of this year. In particular, the group aims to accomplish two goals, says Laurie Davies Adams, executive director of the Pollinator Partnership, a nonprofit group that is coordinating the effort.

First, the consortium hopes to recommend best practices for growers to minimize exposure of forager honeybees to seed dust while maintaining as much forage for honeybees as possible. To meet that goal, the group is trying to better understand the foraging conditions around cornfields at planting time, Davies Adams notes.

Second, the group is evaluating the performance of an alternative lubricant system to minimize the amount of dust generated during the planting of pesticide-treated seeds. Currently, growers use graphite, talc, or some combination of the two lubricant powders. Mixed in with the seeds, such lubricants reduce seed-to-seed friction during planting and improve the uniformity of planting. But even with the use of talc or graphite lubricants, some of the pesticide active ingredient rubs off treated seeds during planting.

The consortium has enlisted the help of government agencies, including the Department of Agriculture, the Environmental Protection Agency, and Canada’s Pest Management Regulatory Agency, to get advice on research protocols that will help the group meet its two goals.

In February, the consortium sent out a request for proposals for work related to the two goals to more than 900 academic and industrial researchers, and earlier this month it announced the recipients of those awards. Altogether, the awards total $320,000, money that was provided by industry and nongovernmental organizations.

Progress reports from the researchers are due in August, and final reports are due in December, Davies Adams says. “Hopefully, by January or February we will determine some possible improvements in corn-planting best practices,” she adds.

Having recognized that bees are being exposed to pesticides during corn planting, industry and regulatory bodies are going after the problem aggressively, says Jeffery S. Pettis, a bee researcher with USDA’s Agricultural Research Service. “New technologies, such as talc replacements, are going to go a long way toward solving this problem.”

Indeed, preliminary results of one new lubricant, a polyethylene wax developed by Bayer CropScience, appear promising. At a Pollinator Summit hosted by EPA earlier this month, William Hairston, director of product development for seed growth at Bayer CropScience, presented data from laboratory studies on the performance of the wax. The data show a substantial reduction in total dust and pesticide active ingredient coming out of the planting unit when using the wax compared with talc and graphite.

In particular, Hairston reported a 90% reduction in total dust compared with talc and a 60% reduction in total dust compared with graphite. With respect to the amount of active ingredient coming out in the exhaust, he reported a 65% reduction compared with talc and a 50% reduction compared with graphite.

Bayer CropScience has conducted field trials to test the performance of its lubricant system in New Zealand and Brazil, and according to Hairston the feedback has been very positive. The company plans to initiate a large-scale program to field-test the system on a minimum of 200,000 acres of corn this year in the U.S. and Canada. “The primary objective is to test a wide range of different planters in a wide range of geographies where we have different environmental conditions,” Hairston notes.

In addition to alternative lubricants, companies are also developing new polymers that help pesticides stick to the seed and thus minimize the amount of contaminated dust generated during planting. But the more polymer that is added, the higher the risk of inhibiting seed flow or germination, says Michael McFatrich, national sales manager at Becker Underwood, a seed treatment company.

Seed flow is important to monitor because seeds need to move smoothly through the planter or they won’t be placed uniformly within each row. Uniform spacing leads to higher crop yields.

Other companies are working on ways to condition seeds to help pesticides stick to them better. Before any polymer or pesticide is added to a seed, the seed must be clean, says Warren Richardson, senior marketing manager for seed treatments at DuPont Pioneer, a seed company. Otherwise, the substance won’t adhere well.

DuPont Pioneer uses specialized equipment involving air systems to remove dust and debris from the surface of seeds prior to treating them. The process ensures that products applied to the seed stay on the seed. “Clean seed is equal to less dust,” Richardson says.

Treating seeds with pesticides and other chemicals is an important part of agriculture today, stresses Raymond P. Knake, a consultant in seed treatment R&D. Treating seeds with neonicotinoid insecticides protects crops from soil insects and other pests. Neonicotinoids also have been shown to improve a plant’s tolerance to pathogens, drought, and heat, leading to higher crop yields.

But not everyone agrees that the benefits of neonicotinoid insecticides outweigh their known risks to honeybees. In late January, the European Commission proposed a two-year ban on the use of three neonicotinoid insecticides on crops in the European Union that attract bees. It took that action after the European Food Safety Authority found significant risks to bees associated with the neurotoxic chemicals. EU member states, however, failed to reach a majority for or against the ban during a vote on March 15, thereby preventing the ban from going into effect.

Meanwhile, bee researchers in the U.S. expect this year to be particularly bad for honeybees. “If I had to predict, total colony losses in the U.S. will be as high as we have ever seen,” USDA’s Pettis says.

Nonetheless, Pettis and others are optimistic that at least the corn dust problem will be solved by next year. “A problem was identified, and we skipped the steps where we pointed fingers at one another for a couple of years, disputed the research, and sued one another,” Davies Adams of Pollinator Partnership notes. “We went right into a problem-solving mode. When people actually sit down and talk to each other, you can come up with some solutions.”


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