berry fields, it is even more important that honey bees are brought in for pollination.
Bumblebees are capable of foraging under more adverse conditions because they are native to the Northern Hemisphere, where they’ve been pollinating plants for tens of millions of years, noted van Westendorp. Although honeybees evolved in a subtropical climate, they are better pollinators, he notes.
John Gibeau of Honeybee Centre in Surrey, says his bees actually pollinate 11 different crops including commercial apples, blueberries, strawberries in the field and greenhouse, currants, cranberries, blackberries, raspberries, kiwi, pumpkin, zucchini and squash. Sometimes, he says one colony can be used to pollinate three crops in a year, because blossom dates differ. Blueberries are among the first berries to flower, usually between mid to late April and the beginning of June, followed by strawberries in May, raspberries from near the end of May through June, blackberries from mid-June to mid-July and cranberries from June through mid-July.
Different berries have different requirements, in terms of the number of colonies required per acre. He says a standard beehive is a box of bees containing nine or 10 frames. At least eight must be covered on both sides and at least four of those must have brood on them. As well, the hive must be relatively disease and pest-free and have a healthy, laying queen.
Van Westendorp goes as far as recommending growers take a course on bees so they are more
knowledgeable about what a healthy colony looks like.
“They pay for the use of the colony so they should know what to look for,” he comments.
A good relationship between the grower and beekeeper is important, he notes. Usually a beekeeper will be proud to show a farmer what it’s all about.
“It’s a question of understanding each other’s needs so as to optimize the opportunity for a productive season,” he explains.
Historically, a beekeeper’s job was simpler, with only a disease called foul brood to worry about. However, in 1990, varroa mites
8 British Columbia Berry Grower • Summer 2010
were introduced to B.C., and the task of the beekeeper immediately became much more complex.
“Beekeeping radically changed. It’s much more complex. It can stump the best minds keeping them healthy and pollinating,” he comments. It’s not just the mite itself, although they can kill a colony of bees. It’s the fact that they are vectors for viruses which can harm bees. They can also weaken the bees’ immune systems so they are more vulnerable to viruses, explains van Westendorp.
He suspects that on Vancouver Island this year, the problem of bee losses may have something to do with the varroa mites becoming resistant to the Apistan used to control them.
The blueberry flower isn’t easy for bees to pollinate.
However, he says there is a correlation between late summers when bees keep flying late into the fall, as they did last year, and overwintering losses. Losses became apparent in January, but the bees themselves likely died the previous fall, he says, so it's too late to determine why they died.
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