A female digger bee collects bright pink pollen in the hairs on her abdomen as she visits a spring beauty flower.
Chuck Kennedy, MCT
BEES AND DISEASE
What: Marla Spivak, a bee expert, will discuss her research on how to keep bees healthy by promoting their own natural defenses.
When: 4 p.m. March 30.
Where: Room 135 of the Continuing Education and Conference Center, 1890 Buford Av., St. Paul.
Cost: Free, but reservations are requested online at z.umn.edu/kermitolson.
Bringing back the bees
- Article by: Jeff Gilman
- Contributing writer
- March 24, 2011 - 8:22 AM
When your garden is in full bloom, it's easy to think that plants can do it all by themselves: grow, flower, even produce fruit. But most plants need a little bit of help with their sex lives.
Since they can't move, plants have a difficult time mating the way that animals do. They've found a way around this problem by using animals, or, more specifically, insects, to do their mating for them.
Plants attract insects by offering them food in the form of nectar or pollen. In the process of eating, the insects get themselves covered in pollen, which is then transferred to another plant by the insect. Without insects, those inadvertent pollinators, your garden wouldn't be able to produce some flowers and most food. Apples, squash, lima beans, cherries, apricots, raspberries -- the list of plants that depend on insect pollinators goes on.
Obviously, pollinators are important, and the most important of the garden pollinators is the honeybee.
As you may have heard, all is not well with the honeybees. And that may have a direct impact on your garden. In the coming years, your vegetable plants and your fruit trees could be less productive if there aren't enough bees to do the pollinating.
Honeybees are being threatened by a new disease known as colony collapse disorder. According to Dr. Marla Spivak, a honeybee researcher at the University of Minnesota, bee colonies have suffered devastating losses every year for the past four years. Although the exact cause of colony collapse disorder isn't clear, gardeners may be contributing to the demise of bees.
First, lots of gardeners like to fill their flower beds with hybridized annuals. But while they look pretty and flower all summer, many of these flowers don't contain much nectar or pollen for bees.
Our use of insecticides also may harm bees. And a new group of insect killers, called the neonicotinoids, is suspected of making bees more vulnerable to colony collapse.
Fungicides, which are used to control diseases such as black spot on roses, and herbicides, which we use to kill unwanted plants such as dandelions, also play a role in colony collapse disorder. Research suggests they may damage the good bacteria in bee colonies and harm plants, such as clover, that keep bees healthy.
The final factor contributing to the disease is one that gardeners can't control. It's a simple fact that bees have a lot of parasites and diseases. Although it's not yet clear if any one parasite or disease causes colony collapse disorder, any number of them could make bees more vulnerable to the disease.
What you can do
As gardeners, we certainly can -- and should -- help bees. Here's how:
• Create a diverse habitat by planting a wide variety of fruit, vegetables and flowers.
Apples, pears and strawberries are excellent sources of food for bees. They also like to visit peppers, kidney beans and eggplant. Flowers that are natural bee magnets include asters, bee balm, butterfly weed, catnip, cosmos, purple coneflower, sedum, sunflower and yarrow. They're also attracted to herbs, such as mint, oregano, chives, rosemary, thyme and sage.
• Allow a few weeds in your lawn. Clover, creeping Charlie and dandelions provide nectar and pollen for bees.
• Avoid the use of insecticides, fungicides and herbicides and be particularly wary of insecticides that contain the active ingredient imidacloprid.
• Create nesting locations by leaving small brush piles, patches of bare soil, piles of stone or by planting clump-forming grasses.
Planting for pollinators
To learn more about bees and other insects and what flowers they're drawn to, go to www.extension.org/pages/19581/conserving-pollinators:-a-primer-for-gardeners
Jeff Gillman is an associate professor of horticulture at the University of Minnesota. He's also the author of three books, "How Trees Die," "The Truth About Garden Remedies" and "The Truth About Organic Gardening."
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