Cultivate a habitat for beneficial insects

By Reeser Manley,
Posted May 15, 2009, at 6:42 p.m.

Last Sunday I saw the season’s first bumblebee. She was foraging for pollen on a wild willow at the edge of Marjorie’s garden, a queen just emerged from her nest (an old mouse hole somewhere nearby, perhaps beneath the rotting stump in the perennial bed) where she had spent the long winter alone. I watched her crawl over the willow blossoms to gather pollen for her honey pot, the small wax cup that will supply her with food as she incubates her first brood.

Soon these first workers will take over the tasks of foraging and incubation and she can devote all of her time to laying eggs. The colony will grow into a legion of bumblebees working from dawn to dusk, rain or shine, all to the end of producing future queens and their mates.

To see these bees dancing in the summer sun, slender stems of catnip blossoms swaying, you would not call it work. Then early one chilly August morning you find a lonely tattered-wing bumblebee, its hairy body glistening with pollen, resting on a sunflower head where it spent the night, too old, too cold or too tired to return to the nest. You think it is dead until a ray of sunlight washes over its body and the legs start to move. Back to work.

As I watched the queen working, I thought about E.O. Wilson’s description of insects as “the little things that run the world.” Certainly, as far as the garden goes, this is true. A healthy, productive garden depends on a diversity of insects: pollinators such as my bumblebee, solitary bee species, butterflies and hawk moths; beneficial insect predators such as hoverflies, lacewings, parasitic wasps and ladybugs; and the pests themselves, such as aphids.

Yes, a healthy garden must include aphids. Without a few aphids and other garden pests, there will be no predators to keep pest populations in balance. And without a diversity of insect species in the garden, there will be no warblers or catbirds, and no cardinals, purple finches or other bird species that we enjoy at our seed feeders. These birds feed insects to their young.

It is time to plan the garden’s insectaries, small patches of annual plants that attract pollinators and predatory insects by providing the pollen and nectar resources they require.

For example, Marjorie and I enjoy nasturtiums, placing them in pots about the garden. Aphids like nasturtiums too, so to make sure that the aphids do not get out of hand, we plant cosmos in small groupings about the garden to attract hoverflies and lacewings. These predators control the aphids to the point where we seldom notice any actual plant damage. Bumblebees forage cosmos blossoms as well.

Other plants to include in your garden insectary include members of the carrot family such as fennel, coriander, dill and Queen Anne’s lace; they are used by a variety of predators and pollinators. Composite flowers, including sunflower, cosmos, yarrows and daisies, will sustain pollinators, both bumblebees and solitary bees, and predators such as lacewings, ladybugs and parasitic wasps. Alyssum, a member of the brassica family, will attract hoverflies.

Plan your insectary for successive bloom from early spring through fall, providing nectar throughout the season. This not only will satisfy the needs of many beneficial insects, but also will provide color in the garden.

A garden insectary should be thought of as an annual feature of the garden. Results are not instant, but the benefits are cumulative. As resident populations of beneficial insects become established, the garden becomes a balanced environment with a complex food web of plants, insects, birds and, of course, the gardener.

Send queries to Gardening Questions, P.O. Box 418, Ellsworth 04605, or to rmanley@shead.org. Include name, address and telephone number.

http://bangordailynews.com/2009/05/15/living/cultivate-a-habitat-for-beneficial-insects/ printed on September 30, 2014