Controlling Pests With 'Good' Bugs

Predator insects are still an organic gardener's best friend

Mike Long walks into The Bug Store just down the road from the Missouri Botanical Garden without even glancing at the displays of gardening accessories. Fancy flowerpots and birdbaths are not his interest today.

Instead, Mr. Long tells store owner Ken Miller that his tulip tree is infested with aphids. He's bugged about the sticky residue they leave when he parks his car under the tree. Long is looking for a "good" bug to solve his "bad" bug problem.

"You're late," Mr. Miller responds before recommending a batch of 1,000 lacewing eggs. "If you release the lacewings in early spring when the tree's leaves are just developing, you'll never see the aphids."

For the last several years, Long has been bringing his insect problems to Miller for natural, chemical-free solutions. Along with millions of other gardeners, he is looking for alternatives to spraying toxic insecticides.

The Bug Store sells about 30 predator insects that control pests. Pitting these good bugs against bad bugs allows gardeners to dispense with chemical pesticides and join the flourishing organic-gardening movement.

"This is the original form of pest control, and it's been around since long before the term 'organic' was coined," says Mike McGrath, editor in chief of Organic Gardening magazine.

The first success story dates back to the turn of the century when the cottony cushion scale, a sucking insect from Australia, virtually destroyed the California citrus industry. The US Department of Agriculture sought out and introduced its natural predator - the Vidalia beetle - and eradicated the scale within a few years.

"It was called the 'miracle bug,' " Mr. McGrath says.

Today, a wide range of "miracle bugs" are being used by farmers, home gardeners, and nurseries. Ladybugs and praying mantises are the stereotypical predator bugs. Yet these are not the most effective, experts warn.

"The praying mantis was one of the old symbols of beneficial insects," McGrath says. "But it's really just a general predator. It will eat a ladybug as soon as it will eat a grasshopper."

Ladybugs are less beneficial than some think because they are more mobile than smaller predators. "You can release them, but you may not be the one that benefits from them," Miller says.

McGrath is more charitable. "They are just so much fun," he says. But to use them to your advantage, gardeners must follow the release instructions carefully. "If you get ladybugs in the mail at noon and release them into a blindingly hot garden on a sunny day, every single one of them will fly away," McGrath says.

Instead, he recommends soaking the garden for the rest of the day and releasing the insects right after nightfall into a thoroughly wet garden.

At The Bug Store, which offers walk-in and mail-order service, three bugs are recommended for 80 percent of home gardeners' pest problems.

*Lacewings feed on all sorts of soft, sucking insects such as aphids, mealy bugs, caterpillars, and scale crawlers.

*Nematodes are microscopic insects that eat insect larvae in the soil, including fleas, grubs, cutworms, thrips, bagworm, and leaf miners.

*Trichogramma, mini-wasps smaller than the period at the end of this sentence, live only to parasitize caterpillars and their eggs. These tiny insects will not sting humans.

The trichogramma seeks out pest eggs and lays its own eggs inside, killing the caterpillar egg within a few days. "It's pretty violent when you think about it," Miller says. "But this has gone on for millions of years. Everything feeds on everything else and keeps it all in balance."

McGrath is less philosophical about it. "If you've ever had caterpillars eat their way through your tomato, you know it's just what they deserve." Miller recommends that home gardeners start a program of releasing beneficial bugs in early spring, about the same time you put out bedding plants or between the second and fourth lawn mowing.

"If you successfully release beneficials, you really only have to do it a few times and then they take care of business themselves," McGrath says. "With pesticides, you're continually spraying."

But buying beneficial bugs is not the only way to increase their presence in your garden. "Every place in the United States and Canada has beneficial insects that can be attracted to your yard," McGrath says.

One way to lure them over the fence is to plant lots of pollen-rich plants and provide a water source. "Grow a lot of plants with very small flowers, such as Queen Anne's lace," McGrath says.

To many gardeners, the idea of introducing or attracting more insects to their yard is unthinkable. "For Americans, not being afraid of an insect is a big step," McGrath says. But if you've "lived with the pests, you can live with the predators," Miller tells his customers.

As their popularity increases and more insectories are established, the cost of beneficial bugs is falling. And as the word spreads, homeowners are leaving the bug zappers of the '70s to rust in garages and putting out the welcome mat for beneficial bugs.

"There's nothing more delightful than watching people release ladybugs into their garden," McGrath says. "It's a remarkable gesture of at least wanting to do the right thing. And if everybody did it, we could pretty much wipe out the pest population in America."

*The Bug Store can be reached at (314) 773-7374.