Alberta has suffered higher than normal losses of overwintering bees for the second year in a row, but Manitoba and Saskatchewan saw some improvement over last year.
Paul Laflamme, head of Alberta’s pest management branch, said preliminary results have found that in some areas, particularly in the Peace River region, losses have been as high as 80 percent.
He added that recent heavy snowfall and a spate of cold weather might have worsened the losses for some beekeepers.
The province is surveying commercial beekeepers, or those with more than 400 hives, to determine the true extent of winter losses and to develop a system of best practices to minimize further damage.
Read Also
Lower nitrogen rates in dry beans could pay off for farmers
Manitoba research is testing whether reduced nitrogen fertilizer in dry beans can maintain yields while cutting costs and lowering greenhouse gas emissions.
“We ran into pretty big losses last year, overall across the province about 30 percent,” said Laflamme. “But the variability was anywhere from 10 to 80 percent.”
Normal wintering losses range from 15 to 20 percent, he said.
Data collected by Alberta’s provincial apiculturalist found that in 2006 the primary cause was infestations of resistant varroa and tracheal mites.
A mild fall also kept bees working late into the season and many colonies failed to produce enough “winter” bees –– specialized offspring that are better adapted for generating body heat to keep the hive warm during the winter.
“That was another contributing factor,” said Laflamme.
This spring, however, the cause has been traced back to growing resistance among varroa and tracheal mites to traditional control measures such as Apistan and Check-mite Plus strips.
“Producers need to start looking at different ways of controlling varroa mites, not just using miticides,” he said, adding that oxalic acid, although more time-consuming, has proven effective against the pests.
John Gruszka, Saskatchewan’s provincial apiculturalist, said that wintering losses at about 12 percent overall are lower this year, according to a recently completed survey of about 40,000 colonies, or roughly half the bees in the province.
“That’s at the lower end of normal,” said Gruszka.
Some beekeepers may have suffered much higher losses than the average because of poor mite control, he added.
The highest losses were in the Carrot River and Nipawin areas, which could indicate that resistant mites have become established in the area. Most Saskatchewan producers are still getting good results with Apistan, he said.
“My suspicion is that the mites there may have developed resistance to both chemical products and this might have caught those guys off guard.”
Beekeepers must remain vigilant about mite levels in their hives, said Gruszka, and test regularly to see if the parasites are developing resistance to control products.
Rheal Lafreniere, Manitoba’s provincial apiculturalist, said preliminary survey results of 30 percent of all colonies in the province have found an average loss rate of 18 percent.
In the coming weeks, depending on the weather, beekeepers will have a better idea of their losses once the bees become more active, said Lafreniere.
“We could have an additional five percent reduction in colony numbers within the next 10 days,” he said, adding that a wintering loss of 20 percent has been the norm for the last five years in Manitoba.
“Last year, at 30 percent, was an anomaly,” he said, adding that heavy fall honey production that year may have crowded out brood chamber space for hive offspring.
“Those areas that were hardest hit were the areas where they had really, really high production,” he said. “Those bees just worked and worked and then got caught by winter.”
