Zapping garden pests used to be as simple as that... one blast with a chemical spray killed them, and they vanished, at least for the time being. After years of searching for the right chemicals--killing good bugs along with bad--more gardeners today are using products that control garden pests effectively and safely without adversely affecting the garden's health.
Many such products are appearing in nurseries now. Some are insecticides derived from plants, and some are modern versions of pesticides our great-grandparents used, such as soaps and oils. One method is devious: pitting bug against bug.
Do these new products and techniques really work? The answer is a qualified yes. Few of them provide the quick fix that some gardeners expect, but all can keep pests' numbers down.
Effective pest control requires close and frequent observation of your plants. If you choose the right plants and keep them healthy and groomed, they can outgrow many pests. A healthy garden has lots of living things-- including a few aphids or whiteflies for beneficial insects to feed on.
On these pages, we look at gardening techniques, beneficial organisms, and nontoxic and low-toxicity chemicals that are practical controls for home garden use.
Before you begin to control a pest, you must identify it. Books, knowledgeable nursery personnel, or county extension agents can help. Then you can choose the best defense.
1. Be a good gardener
The easiest way to control pests is to create an environment that either discourages them or reduces plants' susceptibility to them. Choose ornamental and edible plants that are well adapted to your area.
Adjust planting time. If planting early would avoid a sure-thing pest, do so. Plant corn early to avoid corn ear-worms; plant gladiolus early to avoid thrips. Spider mites are most troublesome when weather turns hot; plant beans early to avoid them. As soon as plants become infested, remove them. Keep records of planting dates and temperatures so you can make adjustments from season to season.
Choose pest-resistant varieties. Certain plants are more susceptible to insect pests than others. Eucalyptus long-horn borer beetles won't damage some species, such as E. cladocalyx. Nematode-resistant tomatoes have the letter N after their names.
Check with your local cooperative extension office for information about edible and ornamental plants best suited to your area.
Solarize the soil. Before planting, you can use the sun to heat the soil-- an effective way to reduce or eliminate soil-inhabiting pests. Just before the hottest time of year (usually mid-July), cultivate soil and remove weeds. Water soil, then lay 1-1/2 to 2-mil clear plastic over it; anchor edges with soil. Leave in place for four to six weeks.
Set out traps. Nurseries and catalogs sell several kinds, for specific pests (snails and slugs, wasps and whiteflies). To trap earwigs, put short sections of garden hose, rolls of corrugated cardboard, or rolled-up newspaper on the ground.
Use barriers or row covers. Often the easiest way to eliminate pest damage is to place a physical barrier between the pest and your plant. To thwart cutworms and snails, put bottomless cans around vulnerable seedlings. Floating row covers of spun fiber or plastic applied before seedlings emerge make an impenetrable barrier to pests, especially tough-to-control ones like aphids, cucumber beetles, flea beetles, root maggots, and whiteflies.
Copper bands around trunks of shrubs and trees block snails. Sticky barriers stop or slow ants, snails, and beetles from climbing. They're available at nurseries as sprays, in squeeze tubes, or in tubs (vegetable gum-based products are less harmful to plants than petroleum-based ones). Be prepared to renew them frequently, and don't let pets or children play near them (they're messy).
Wash plants. …