Friday, August 12, 2011

Natives in the Garden

It's been five years since honeybees started dying in large numbers across the country. Scientists are still trying to figure out why and what they can do about it. Eric Mussen, a university extension bee specialist at the University of California at Davis, says that beekeepers are still losing, on average, 30 percent or more of their colonies each year. Not everywhere, of course, but in enough places to make Colony Collapse Disorder a continuing puzzle.

Meanwhile, some farmers are wondering whether – and how – they can get native bees to take up the slack. There are more than 4,000 species of native bees in North America, ranging from the size of a fruit fly to nearly three inches long. Like their honeybee cousins, native bees work hard to gather pollen to feed their young and, in the process pollinate such crops as tomatoes, eggplant, watermelons and other melons, zucchini, cucumbers, winter squash and pumpkins. They also pollinate strawberries, raspberries and blueberries.

Native bees, it turns out, work harder than their honeybee cousins. Squash bees get up earlier in the morning and bumblebees keep working in cold and wet weather. Not only that, but it takes only 250 blue orchard bees (Osmia) to pollinate an acre of apple trees – a job that would normally require 15,000 – 20,000 honeybees.
Native bees also make honeybees work harder. Scientists studying pollinators on hybrid sunflowers discovered that when wild native bees were around, honeybees were up to five times more efficient in pollinating the sunflowers. Apparently the natives made the domesticated bees nervous, causing the honeybees to switch flowers more frequently.

So, how do farmers attract those hard-working natives to their farms?

 “We let things go a little wild,” says Teresa Vanek of Red Tail Farm in Trumansburg, NY. She and her partner raise bees and sell the honey. They also grow a diversity of vegetables on their four-acre organic farm. So they make sure there are lots of flowers growing on their farm to provide nectar for bees.

When harvesting broccoli and related crops they leave older plants in the beds to flower, instead of pulling them out and tossing them in the compost. Bees love the yellow and white flowers produced by arugula, radishes, mustards and broccoli-raab. They also let their cover crops –buckwheat, white clover and red clover – go to flower and plant blocks of sunflowers to attract the pollinators.

Does it work? “We have a lot of wild bees,” Vanek said, noting that bumblebees and sweat bees are abundant on her crops.

1 comment:

  1. The orchards around me are experimenting with mason bees and bumblebees--they seem to be working well, judging from the different kinds of bees that are coming to my garden. Thanks for the well-written article!