More Bee News
Several stories from Europe and North America circulated in the past month regarding bee deaths and colony collapse disorder (CCD). In Germany, the insecticide clothianidin has been implicated in a die-off of adult bees, which may seem strange for a seed treatment. The EPA has met with German officials regarding the incident, and based on the toxicity pattern and temporal nature of the incident, do believe it to be linked to CCD. What is believed to have happened is that late corn planting (with treated seed that did not have a sticker), overlapped with canola bloom. Dust from the corn field was blown onto the canola, and the bees were exposed to this dust.
In Canada, the experience of beekeepers echoes that of those in the U.S., where 36 percent of the nation's commercially managed hives have been lost since last year, according to a survey commissioned by the Apiary Inspectors of America and released in May. Paul Laflamme, head of Alberta Agriculture and Food's pest management branch, said that while many U.S. losses have been blamed on CCD, no cases of CCD have been confirmed in Canada.
Instead, the two parasitic mites that started infesting bee colonies in the mid-1980s are seen as the primary reason for the failure of colonies across Canada. The tracheal mite, believed to have entered the U.S. from Mexico, sucks blood from honeybees by burrowing into a bee’s windpipe. The larger Varroa mite lives on the outside of bees and destroys the insects’ reproductive cycle. Beekeepers have been using pesticides but it now appears the pesticides have lost their effectiveness. “There are only two miticides registered in Canada to control these mites, and the mites have developed a resistance to both of them,” said LaFlamme.
John Gibeau, the president of the British Columbia Honey Producers Association, said there are natural treatments for dealing with the mites that don't require pesticides, including the use of formic acid, thyme oil and a process called drone brood trapping, which isolates the most likely place for mite infestation from the rest of the hive. But he said these measures are most effective when alternated with pesticide use, and natural methods and practices such as drone brood trapping require far more intensive management.
Paul van Westendorp, the provincial apiculturist at the B.C. Ministry of Agriculture and Lands, said the problem with the Varroa mites in particular is that they are vectors for a host of diseases and viruses, including the Kashmir Bee Virus, which was first diagnosed in Canada and had a devastating effect on the honeybee population. “We're talking about the most virulent pest known to bees. It’s a pretty sophisticated creature on its own and now it’s transmitting viruses,” said van Westendorp. “To find a product that's virulent to mites but harmless to the bee is a tall order.”
Beekeepers deal with colony losses by either importing colonies from countries like New Zealand or splitting their existing colonies. But many of the colonies still functioning are already very weak. This has accelerated the exit from the industry of many commercial beekeepers, said van Westendorp, putting a further strain on those who are left to travel further afield to pollinate. The stress of transport is a growing concern for beekeepers, particularly since many of the U.S. colonies that were wiped out from CCD were migrant colonies, traveling across the country to pollinate different crops in different states. The cause of colony deaths could be mites, viruses, weather, stress or beekeeper error, or a combination of any number of these factors and the only protection is constant vigilance said van Westendorp. (EPA OPP Update, 7/1/08 & CBC News, 6/10/08).
