Caution urged on laying blame for honey bee deaths

Friday, July 19, 2013

by DAVE PINK

The increasing use of insecticide-treated seed may be the leading reason for the continent-wide die-off of honeybees, says the president of the Ontario Beekeepers Association.

“It poisons the whole plant,” says Dan Davidson. “This is not the way we should be going.”

He says that tests on the dead bees confirm they were killed by the insecticides contained in field crops such as corn and soybeans, and he doesn’t want to see any time wasted before the neonicotinoid family of pesticides is taken off the market.

But other honeybee experts aren’t yet ready to point fingers. There are several other likely suspects, and lots more research to be done, they say.

They are hoping that a consensus can be reached as the freshly appointed Bee Health Working Group carries on with its task of framing a list of bee-health recommendations over the next year. The formation of the working group – which includes beekeepers, farmers, agri-business representatives, scientists and staff from both the federal and provincial governments – was announced by the Ontario Ministry of Agriculture and Food earlier this month. It met for the first time last week, and is to meet again in August.

The ministry has not yet released a list of those on the working group, but Davidson says that he and two other members of the OBA will be a part of it. “We feel very positive about it, and we’re hoping for great results,” he says. “But we’ve only had one meeting, and the focus has not been narrowed down.”

Provincial apiarist Paul Kozak, another member of the working group, cautions against jumping to any conclusions until all the data from all the experts is in. “We have to take a look at the long-range trends. We want to look at the overall picture and we have to be cautious in reading numbers from one year to the next.”

He says that the abnormally high winter die-off of the bees was first noticed in 2007. Up until then, beekeepers regarded a 15 per cent winter die-off as normal, but from 2007 to 2009 the province-wide mortality rate averaged about 33 per cent. In 2010, it was 20 per cent, then in 2011 it was about 43 per cent, but in 2012 it dropped to slightly less than 13 per cent. This year’s numbers have not yet been tabulated.
Pesticides, he admits, could be part of the problem. “But beekeepers have always had good success in dealing with pesticides,” says Kozak.

He says there are no obvious answers and no shortage of possibilities. “It all depends on who you talk to.” But, he adds, the growing incidence of parasites in the hives, such as the varroa mite, has to be watched very closely. “Almost every bee colony has them,” he says.

Luc Bourgeois, the research and development manager with Bayer CropScience, says the issue is “incredibly complex” and that there could be several reasons for the bee crisis. It’s possible that a virus is responsible for the die-off, a situation made worse by the annual spring transfer of bees from Ontario and Quebec to the Atlantic provinces to pollinate the fruit crops, where bees from one region come into contact with bees from another, making the spread of a virus more likely.

It’s a practice that’s also widely used in the United States – which is experiencing a similar crises – where bees are trucked throughout the country to wherever they are needed for pollination.
Or, says Bourgeois, bee stress could be related to their pollen diet, suggesting that the nutritive value of some field crop pollens is better than another.

Bayer, which develops and markets some widely used insecticides, including seed treatments, installed three beehives at its research farm near Guelph this spring for observation.

Bourgeois says the treated seed has become popular with field crop growers because it protects the seed and the young developing plants from insects, and has been proven to increase yields.

It’s not as if bee scientists aren’t alert to the threats posed by treated seeds, says Tracey Baute, a field crop entomologist with the ministry. The question is: How are bees being exposed to the pesticide?

She is currently conducting a series of field trials at the University of Guelph’s Ridgetown campus to determine if the dust that results from the planting process is to blame. New pesticide formulations and new lubricants on the planters may be an answer, she says – but she doubts that it will be the ultimate solution.

“There are a lot of gaps in our knowledge and a lot more research needs to be done. There are a lot of variables,” she says. “And if the neonicotinoids were banned we are not going to see the problems go away.”

There are 3,000 registered beekeepers in Ontario, with about 100,000 bee colonies. “Honey is just a by-product,” says Kozak. “Their real value is in the pollination of the crops. They are a spoke in the wheel of agriculture.”  BF