Keep Bugs Away Without a Spray

Summer is one month away, but I'm already preparing a giant picnic in the back yard. From the swelling of the first pea to the fall of the last apple, grandchildren and other visitors will come to graze the garden, a tablecloth spread for random snacks and the household's year-round supply of produce. This hospitality requires that the garden be pesticide-free. The kids are too young and I am too old to keep track of the "safe days to harvest" one must observe every time a poison is applied to food. More important, I've found in my years of gardening that such a program is unnecessary.

My approach to unwelcome insects consists of a few steps that have stood me in good stead. Here they are, in order of chronology and level of importance:

Step 1. Enlist the help of natural predators by maintaining a nontoxic environment. Keep the yard safe for birds, predatory wasps, lady beetles, toads, frogs and hundreds of other creatures that eat garden pests. Eliminating too many pests by spraying can backfire by robbing predators of their food and thereby decreasing their numbers. Also, any pests that survive spraying are apt to breed offspring with pesticide-resistant traits.

Step 2. Grow healthy plants. Plants under stress are more vulnerable to bugs and diseases, so try to give a plant what it needs. If you see predation, tick off the things the plant might lack, and consider whether another variety might do better. Plants need:

-- Soil rich in organic matter, with a wide range of nutrients and an aerated, friable structure.

-- Adequate light, water and air circulation.

Step 3. If a pest shows up in large numbers, use mechanical means to save the crop. Hand-picking, though tedious, can usually reduce enough numbers, especially with large creatures such as tomato hornworms, potato beetles (the eggs, the larvae and the adults) and Japanese beetles. That also works for cutworms, which sleep just under the soil surface next to plants they've nibbled. A vacuum cleaner with a slot attachment works well for insects easily startled into motion, such as leafhoppers and cucumber beetles. Tent caterpillars can be poked out of their nests and drowned. Aphids and mites can be knocked off with water from a hose. Simple traps, such as boards or half-filled bottles of beer on their sides, will capture slugs and snails.

Step 4. Erect barriers. If you are expecting a visit from a frequent pest, spread a floating row cover over crops before it can move in. Potato beetles, carrot flies and root maggots on brassicas are easily controlled this way.

Step 5. As a last resort, apply only the most harmless, selective, targeted treatment, such as a squirt of vegetable oil to the young silks of corn ears to foil earworms. Even supposedly benign products such as Bt, rotenone and agricultural soap sprays carry a price tag in terms of money, time and risk to the environment.

Step 6. See Step 1.