It's the time of the year when more and more bugs seem to surface, ready to make mincemeat of your melons, assassinate your asparagus and devour your dahlias. Your immediate reaction is to see red and reach for the Malathion.
Well, you don't have to. There are alternatives far more benign and equally effective, though the world of alternative pest control is not populated by the slick marketing executives who make chemicals so easy to buy and use. In fact, "organic" or "natural" pest control seems to be characterized by a maze of complicated terms and even conflicting claims.
But once you get past the subject of "environmental management" -- such as keeping the garden clean, selecting resistant plants, companion planting, soil balance and general garden preparation and maintenance, all of which are admittedly very important -- alternative pest control falls into a handful of basic categories. beetle traps. Baited with a powerful lure, they're one of the most effective ways of controlling those voracious beetles. There are other insect traps, some of which you can easily make.
For instance, a reader wanted to know what to do about slugs. This year has been particularly good to slugs, so much so that many gardening stores have already run out of commercially manufactured slug bait. Shallow saucers of stale beer placed among the strawberries at night will kill off large populations of slugs, all of which are downright alcoholics and will happily drown in the beer. Don't waste good beer; any cheap beer will do. PREDATORS: Releasing beneficial insects is helpful, but it takes years to build up enough of a predator population to make any real difference. Among the good insects are ladybugs, lacewings, preying mantises, trichogramma (tiny non-stinging wasps) and other predatory wasps. There are also parasites that attack certain insects. Such parasites and predators are available through many garden and seed catalogues. If you choose to go that route, however, view them as a long-term approach to gaining control. BIOLOGICALS: These are pathogens -- viral or bacterial diseases -- released or sprayed to affect certain types of insects at certain stages. The most commonly used biological is Bacillus Thuringiensis (BT), marketed under a number of brand names, the most common of which are Dipel and Thuricide. BT controls a huge number of pests in their larval stage when they're doing the most damage: gypsy moths, cabbage looper, the leaf roller and so on. BT also kills the larva of non-pests, such as harmless butterflies and moths, so use it with discretion. BT can be used effectively all through the year and kills pests quickly. Repeated applications may be needed because it breaks down so rapidly that it loses its effectiveness within 24 hours. Other biologicals include milky- spore disease, which targets Japanese beetle larva but also kills many other underground, root-eating bugs, and grasshopper spore, which infects grasshoppers and crickets. New biologicals are being developed almost annually. One leader in the field is Reuter Laboratories in Gainesville, Virginia. BOTANICALS: Considered true "pesticides," these plant-based sprays and dusts are used mainly for immediate control, once the pests have surfaced and are doing their damage. The use of botanical pest controls is most effective if your garden is overrun with various insects right now and you're pulling your hair out. Like BT, botanicals are considered broad-spectrum -- they kill indiscriminately and they'll get rid of ladybugs right along with leafrollers. Like BT, they also break down in the environment within 24 hours. The two most commmon botanicals currently available are pyrethrum and rotenone. Pyrethrum is derived from the chrysanthemum family and rotenone is derris root. Both are widely available through garden stores. But your best bet, if you want to stick to the strictly organic route, may be to buy them through the catalogues or directly from stores that deal with natural and organic pest controls, especially in the case of pyrethrum. The reason is that, according to some experts, many commercially manufactured "organic" pest controls add chemicals to the carrier, the liquid that dilutes the poison itself. And second, pyrethrum has been duplicated in the lab. Called pyrethroids, these substances are chemically identical to the natural pyrethrums. But according to Tom Harding, who operates Progressive Agrisystems, a botanical research and marketing outfit in Pennsylvania, "For some reason that we don't understand, the insect population has a tendency to build up a resistance to synthetics in a matter of years." Some commercial pyrethrum- based insecticides are actually pyrethroids, so read the label carefully when you buy. INSECTICIDAL SOAPS: Most gardeners and indoor-plant growers have heard of and followed the practice of rinsing plants off with soapy water to rid them of certain soft-bodied damaging insects. According to Bill Wolf, owner of the Necessary Trading Company near Roanoke, there's an ingredient in ordinary soap that acts as an insecticide on these pests. However, Wolf says, "you have to pour so much soap onto the plants to get really good control that it would damage the plant itself." Wolf's insecticide soap contains a more concentrated version of the ingredient that kills pests. Wolf is particularly fond of insecticidal soap in the control of aphids, the scourge of many a garden. LIQUID SEAWEED: Concentrated kelp, heavily diluted with water, comes highly recommended by Wolf not only as a pest-deterrent but also, more importantly, as a stress-reliever for the plants. It's sprayed directly on the plant foliage (don't worry, it won't make your broccoli taste like seaweed) and gives insect-damaged leaves a boost that leads to rapid recovery and additional strength to fight off disease. For the layman who's trying to wend his way through the maze of information on alternative pest control, the most useful tool I've found comes from the Necesary Trading Company. Wolf has devised in his catalogue a list called "Necessary Bioselector," which lists two score common garden pests and what to do to control them using plant selection, traps, predators, biologicals and botanicals, among other methods. And if you're still puzzled by all the terms and options, Necessary Trading also sells an organic plant protection kit, $29.95, which essentially tells you exactly what to do and furnishes the what to do it with. Companies that deal in the controls mentioned in this column include: NECESSARY TRADING COMPANY, Main Street, Box 305, New Castle, Virginia 24127. BURPEE'S, Warminster, Pennsylvania 18974. REUTER LABORATORIES, Gainesville, Virginia, sells traps and biologicals directly to the consumer. For ordering and information, call 691-0035. PLANTS AND FLOWERS GARDEN DEMONSTRATION -- There will be sessions on planting, insect identification and control, weed and disease control and harvesting of garden vegetables at Watkins Regional Park on Saturday. The class is at the Cooperataive Extensive Service Demonstration Garden, site 82 (under the power lines) from 10:30 to noon. Participants can pick up a garden demonstration newsletter at the nature center. The park is at 301 Watkins Park Drive in Upper Marlboro. Call 952-3226 for more information. HORTICULTURAL COURSES -- The U.S. Botanic Garden Conservatory is holding a free one-hour class on informal floral arrangements using summer flowers on Friday and Saturday at noon and 2. Pamella Marshall withe the D.C. Cooperative Extension Service will also teach a short course on how to dry flowers for future use. The conservatory, at First Street and Maryland Avenue SW, is open daily from 9 to 9 through August. Call 225-7099.