See that nasty-looking creature above? If you come across it, back off.
This ruthless killer--the larva form of the convergent lady beetle--is the Arnold Schwarzenegger of the garden. It exterminates up to 400 aphids, whitefly, mealybugs or other undesirables before its transformation into an adult ladybug.
"And to think I've been squishing them for years," sighs Anaheim gardener Dennis Glowniack, who just learned the larvae's true identity. "Ladybug larvae are something you definitely want in your garden. They eat twice as many pests as the adults."
If Glowniack, a member of the California Organic Gardening Club and a practitioner of organic gardening methods for nearly 30 years, can make that kind of mistake, imagine what those of us without his experience are doing.
Nick Nisson, an entomologist with the County Agricultural Commission, cites another common example of overkill.
"One beneficial (insect) that people bring in all the time thinking it's a pest is \o7 Cryptolaemus montrouzieri, \f7 the mealybug destroyer," he says.
He describes a typical scenario:
"Norfolk star pine is prone to golden mealybug (a sap-sucking pest), but people don't usually notice the mealybugs until they start producing enough honeydew to be messy. Then they notice insects crawling on the leaves. At that point what they're probably seeing is the mealybug destroyer, which (in its larva stage) looks almost like a mealybug, except that it's larger. That's when they haul out the chemicals.
"It's like killing the rescue team."
The answer to what you should do about most bugs, says Nisson, is nothing.
"If a pest is there in large numbers, be patient and some beneficial will come along and take care of the problem for you," he says. "Poisons are rarely necessary."
Attract beneficial insects to your garden ahead of pests by planting lots of pollen and nectar plants, which adults insects use as a supplement to or as their sole diet, suggests John Kabashima, environmental horticultural adviser at the Cooperative Extension. (Many beneficial insects are only predacious during their larvae stage.) And avoid using toxic sprays and dusts.
If you or a garden predecessor have been using a broad spectrum poison which kills good and bad bugs indiscriminately, you may want to import some beneficial insects into your garden to speed up the process of bringing it back into balance.
One of the best predators for the home garden, Kabashima and Nisson agree, is the green lacewing \o7 (Chrysopa carnea). \f7 Though lacewings have earned the nickname "aphid lions," they'll devour any pest without a hard shell including aphids, mealybugs, whitefly, small caterpillars, mites, thrips and immature scale.
Another advantage of lacewings is that, unlike ladybugs, they're not the roaming kind. One purchase is often all that's needed to establish a local population.
That has been Glowniack's experience.
"I bought some lacewings about eight years ago to combat whitefly and mealybugs on my citrus trees and spider mites in my boysenberries, and they've been around ever since," he says.
"They're very small (less than an inch long), green like plants and have transparent wings. So they're well camouflaged. But they're there if you look for them."
Another good buy in beneficial insects is \o7 Encarsia formosa, \f7 a minute parasitic wasp that preys on greenhouse whitefly, a sap-sucking pest that causes wilting, yellowing, loss of leaves and a black, sooty fungus in greenhouse plants and, in subtropical climates like Southern California's, in outdoor plants as well.
\o7 E. formosa \f7 wasps feed on whitefly larvae and lay their eggs in them. The \o7 Encarsia \f7 eggs hatch into tiny worms that feed off whitefly larvae and kill it before emerging as adult wasps.
Jean Graham of Irvine testifies to \o7 E. formosa's \f7 efficiency in combatting whitefly.
"I had a very bad infestation on my apple tree," she says. "The honeydew from the whitefly produced a lot of black mold, and the tree looked awful."
Graham put strips of whitefly parasitic wasp eggs on the branches, as recommended by her local nursery, and, she says, "it cleaned up the tree in two weeks."
\o7 E. formosa \f7 does not parasitize all forms of whitefly, however, warns Nick Nisson. Identify your problem before spending your money, he advises.
Ladybugs are undoubtedly the most widely purchased beneficial insects in the country, but in the opinion of many experts they are not the best use of gardening dollars.
"My theory is they tell you to release ladybugs at night, so you can't watch them fly away," says Kabashima. "The convergent lady beetle is migratory by nature. No matter what you do, they won't hang around."
As long as ladybugs decimate the worst of a crop of pesky pests before they split, who cares?, counter other gardeners.
"I use ladybugs on my roses every year," says Mary Lou Heard at Heard's Country Gardens in Westminster. "If they clean out the aphids and then move on, that doesn't both me. They've done their job."