Mild winter credited for low beehive losses

Most prairie residents were delighted by this year’s mild winter, but beekeepers were particularly pleased because only 15 percent of their hives failed to make it through the winter.

Results aren’t finalized yet, but preliminary figures indicate that 16 percent of hives were lost in Manitoba, 15 percent in Saskatchewan and 15 percent in Alberta.

Those over-wintering losses are much lower than previous years, particularly in Manitoba, where beekeepers have averaged 30 percent losses over the last five years.

“This is more reminiscent of long-term winter losses, which were generally assumed to be around 15 percent,” said Rheal Lafreniere, Manitoba’s provincial apiarist.

“(It’s) down substantially from last year, for sure, when it was around 34 percent.”

A combination of factors helped the bees survive the winter, including mite and disease control, but Lafreniere said weather likely had the largest influence.

After reviewing beekeeper surveys, Lafreniere noticed that only a few hives died from starvation over the winter.

“We did get a very nice fall, so bees were able to provision their hives very well,” he said. “And spring came early, so the bees were able to fly (early) … and the stress level from their winter was relieved by having the spring come a little earlier.”

The bees also benefited from warm temperatures at key periods in the fall. Most beekeepers on the Prairies now use Apivar to control varroa mites.

To effectively kill the mites, the bees must be active to distribute the chemical throughout the hive.

“So in that nice fall, the (bee) activity was high for a long time period,” Lafreniere said.

In Alberta, overwintering losses in 2011-12 were roughly half of the losses in 2010-11, when 29 percent of beehives didn’t survive the winter, said Medhat Nasr, Alberta’s provincial apiculturist.

Although the mild winter helped, Nasr said a surveillance program for mites and disease is also part of the story.

Since 2008, when 44 percent of beehives in the province died over the winter, Alberta beekeepers have carefully monitored mite and disease levels in the spring and fall.

“Most beekeepers, right now, have adopted this surveillance of mites and nosema,” Nasr said. “So they are able to determine (infestation) and respond in time.”

Four beekeepers in the Peace River region had overwintering losses of 75 percent, but Nasr said those exceptions are easily explained.

“The treatment system for nosema failed in these operations. So it’s good when you know what is the cause of winterkill.”

Minimal hive losses should help beekeepers reinvigorate the in-dustry.

When colonies die, beekeepers must split their active hives and spend more time and energy rebuilding bee populations.

“When you start getting 30 percent winter losses, it’s almost an unsus-tainable number,” Lafreniere said. “You’ll see the overall numbers in the province start to diminish if you have to replace 30 percent of the colonies.”

More bees foraging for pollen and nectar aids the financial bottom line because more bees usually means more honey production and more revenue.

Although the decrease in overwintering losses is welcome news, Canada’s bee industry must remain vigilant. Bee experts need to continue their work on superior genetics and other approaches to protect colony health for the long run.

Apivar is the only product that is effective at killing mites, while only one agent, fumagillin, can control nosema.

“If the mites develop resistance to it, we don’t have a replacement,” Nasr said. “We don’t have any backup for any treatment…. Fumagillin, we don’t have a replacement for it.”

The Canadian Association of Professional Apiculturists is expected to release official statistics on overwintering losses later this month.

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