When it comes to controlling bugs in the garden, you've got several choices. One is to ignore them, in the hope that they'll go away. But they're hard to ignore, and they probably won't go away by themselves.
Another is to bombard them with chemicals, which will treat the symptoms by getting rid of the bugs temporarily, but won't cure the disease. You'll have to use chemicals repeatedly within the year and then again and again each year after that. Chemicals, as we all know, are also bad for the environment -- for good critters who are trying to help you in your battle against bad critters and for the gardener who plans to eat his vegetables.
A third approach is to use host-specific biological controls, a fairly new method of natural and organic pest management. The research has been around for years, pursued mainly by the U.S. Department of Agriculture. But until recent years no one was making, on a commercial basis, viruses and bacteria to infect specific pests in specific stages. They're increasingly popular now, however, given the expense of toxic chemicals.
What's important to realize about biological controls is that they get at the heart of the problem by using the insects against themselves. They often take longer to work, but they're far more effective in the long run than chemicals.
You probably won't see any immediate benefits, but you ought to start applying them now, particularly against Japanese beetles. A case in point came last week from a caller who wanted to know why his lawn was riddled with little holes. Chances are the lawn is infested with Japanese beetle larvae, which nibble at grass roots and later cause brown patches in the lawn. As mature beetles, they are voracious eaters of almost any vegetation. In the vegetable garden they can do untold damage if allowed to fly about unchecked.
One of the most effective methods of controlling them is by infecting them in their larval (fat white grub) stage with milky-spore disease. Milky spore is a virus that affects more than 40 species of white grubs (including the June bug), many of which damage the roots of plants.
Fortunately for area gardeners, we have nearby a lab -- one of only a handful in the country -- that manufactures and sells, among other products, milky-spore disease for use on home lawns.
"You can apply milky spore any time the ground isn't frozen," says Zach Richards, a spokesman man for Reuter Laboratories in Gainesville. "What people have to understand, though, is that you really won't see any effect for a couple of years. The first year will put a dent in the population, but it won't be until the second or third year before you really notice" the absence of Japanese beetles.
The milky spore comes in a powder that's "injected" into the soil in a grid pattern. As the grub comes along, eating through the soil, it will hit one of the "plugs" of milky spore, become ill, continue its trek through the ground, and then die, releasing more spores in the spot in which it died. This creates another milky spore "plug," and the next grub will come along, eat the spore and so on. The heavier the infestation of grubs, the faster the virus will spread and the more effective the treatment.
Japanese beetle grubs are easy to spot. They are two or three inches long, very fat and have a grayish area on one end and a brown head with six little brown legs behind the head. When you turn the soil over, you'll find them curled head to rear like a sleeping cat. They grow in undisturbed soil -- that is, ground that isn't tilled or cultivated -- which usually means lawns, golf courses, fields or pastures.
If you suspect an infestation of the critters, take your shovel and dig out a few patches of lawn. Just push your spade down six or eight inches and turn over a clump of grass. If you see what might be a Japanese beetle grub, you can send it in to Reuter Labs for confirmation, or you can go right out, buy some milky-spore disease and apply it yourself. Quite a few retailers sell it around Washington or you can get it through Reuter.
Because the manufacture of milky spore is extremely labor-intensive -- the lab must collect by hand up to 100,000 grubs each spring from lawns and golf courses around Gainesville in order to produce the spore -- it tends to be expensive, initially. For a quarter-acre lawn, it costs about $20. But when you consider the duration of the spore's killing power, the cost is really worth it.
Once established in an area, milky-spore disease will maintain its effectiveness and in fact spread for up to 20 years. It's far more effective if injected or spread over a large area. The folks at Reuter work closely with homeowner and community groups to infect larger areas than an individual backyard. The problem with being the only guy on the block to apply milky spore is that you're not going to protect your garden from drop-in beetles once they're grown up and on the wing.
To help control the mature beetle without using chemicals, Reuter manufactures a plastic trap, an improvement over the standard metal traps that tend to bend and rust. The lure, which, like beetle traps, is readily available at hardware stores and garden centers, is a sweet, sticky substance so powerful that if you open the can outdoors in June, you'll be bombarded by beetles.
The folks at Reuter also are coming up with some other innovations in biological control. In addition to the milky-spore disease, which launched the company 10 years ago, Reuter now makes a grasshopper spore; a biological mosquito control (BMC), which consists of a larvacide that is also effective against black-fly larva; and a bright yellow piece of plastic covered with a sticky substance, the combination of which attracts anddcaptures many different insects in the house and garden.
For more information on Reuter biological pest- control products, contact Reuter Laboratories, Gainesville, Virginia 22065. Call 703/691-0035. FLOWER & PLANT SALES AZALEA MART -- Saturday at 8, Suburban Trust parking lot at the corner of University Boulevard and Grandview Avenue in Wheaton. Large selection of evergreen and deciduous azaleas on sale. Sponsored by the Brookside Chapter of the Azalea Society of America. Proceeds go for educational and civic activities. Call 831-7561 for information. PLANT SALE -- Saturday at 8, Grand Union parking lot, Falls Church, at the corner of Broad Street and Virginia Avenue. Annuals, perennials, vegetables, small shrubs, ground covers, herbs and potted plants on sale. Sponsored by the Falls Church Garden Club. Proceeds help fund club activities and a scholarship for a horticultural student at Northern Virginia Community College. For information, call 241-0972.