Over time, growers have increased number of bees introduced into fields,
and crowded bee shelters
|14-16,000 female bees per acre
|140-160,000 female bees per shelter
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Density dependent mortality factors like chalkbrood and parasites have
Over the years, growers have increased the number of bees that they
introduce into their fields and into crowded bee shelters, until now
densities of 14-16,000 female bees per acre, and 10 times that number per
nesting shelter are introduced. With such large populations, it is no wonder
that density dependent mortality factors like chalkbrood and parasites have
increased. Furthermore, bees from Canada have been relatively inexpensive,
reducing the incentive for Northwest growers to manage for high bee return.
When bee prices are high and/or seed prices are low, concern increases about
improving bee yields.
The desire for a sustainable yield of bees in the Northwest is not
universal. Canadian alfalfa seed growers donít want it; they get a large
portion of their income from selling bees. The growers who use the largest
bee populations realize that these populations are not sustainable, but
apparently are resigned to this. As one grower puts it, bees are like
fertilizer, an expense that you budget for each year.
A few growers, particularly in isolated areas, are able to provide their own
bees without buying from Canada, because they use relatively low numbers of
bees, and/or supplement bees from their fields with bees trapped in nearby
wild areas. They have achieved local sustainability, but note that they
still may have to supplement the bee populations in their seed fields.
Rather than buying from Canada, they put in their own time and equipment to
find the excess bees.