Pesticides designed to protect honeybees against the varroa mite have been losing their effectiveness, leading to heavy colony losses across Canada in recent years, researchers say. (CBC)

Vancouver Island beekeepers say 90 per cent of their hives have been wiped out by a lethal combination of disease and a long summer last year.

Vancouver Island is home to a quarter of all the honeybees in British Columbia, but commercial operations were devastated over the winter by a high mortality rate for honeybees.

Scientists believe the mass die-off was caused by several factors, including the varroa mite, which makes bees susceptible to other viruses. A long summer also meant bees continued collecting pollen for a much longer time, which weakened them and make them more vulnerable over the winter.

The result has been a disaster for Vancouver Island producers, but it won't affect the price of honey, according to Paul van Westendorp, the provincial apiculturist at the B.C. Ministry of Agriculture and Lands.

'What is important is crop pollination — no bees, no berries.'— Paul van Westendorp, provincial apiculturist

The island isn't a large honey-producing region. Instead, most island bees are sold to other producers in more agriculturally intensive regions to build up their hives quickly during the honey-producing season.

But van Westendorp is concerned about the same trend showing up in the rest of the province, where honeybees play a critical role in agricultural pollination.

"In an agricultural context, what is important is crop pollination — no bees, no berries."

However, early anecdotal reports from beekeepers in the Interior are reassuring, van Westendorf says. Most say they aren't seeing massive die-offs but won't know for sure until April, when the bees become more active.

In the meantime, some island beekeepers say they will import new bees from New Zealand and other areas but they warn the cost many drive many of them out of business.

Pesticides designed to protect honeybees against the varroa mite have been losing their effectiveness, say agricultural researchers, leading to heavy colony losses across Canada in recent years.