Whenever you see insects in your garden, remember this: Most are no threat to plants, many are even beneficial, and all of them, even the pests that eat your plants, are an integral part of the ecosystem you are cultivating. But what do you do when the pests seem to have the upper hand? You don't want to enforce a "no-fly zone" with pesticides. They're dangerous for you to have and to use, and they harm wildlife and contaminate water. Instead, use safe, organic techniques and products to keep the pests in balance.
Grow healthy plants. The best defenses against insect attack are preventive measures. Pests target weak or unhealthy plants, so choose plants that are suited to the conditions you are putting them in and they'll be less stressed. Don't let plants be too wet, too dry, or too shaded. Use lots of compost, but be sparing with high-nitrogen fertilizers, if you must use them at all.
Integrate, don't segregate. Mix different vegetables, herbs, and flowers together in your beds. This keeps pests from zeroing in on a whole crop of their target plant.
Encourage Pests' Predators. The most effective and natural way to control pests is to rely on the food chain. Plant herbs and flowers among your vegetables to lure predatory insects such as ladybugs and green lacewings, which feed on flowers' nectar while their larvae consume pests. Put out a birdbath to enlist the appetites of songbirds to your cause. Treat toads, lizards, and garter snakes as welcome allies, too.
Build Barriers. Row cover is a woven fabric that lets light, air, and water reach plants, but keeps pests (including deer) away from them. You'll find it in local garden centers, in catalogs, and online. The best-known brand is Reemay.
Target The Treatment. When prevention is no match for infestation, take the time to choose the right organic tool to solve your problem. Start by making sure you have correctly identified the pest and confirmed it is the cause of the symptoms you've found. Consult your local Cooperative Extension office (csrees.usda.gov) if you need help. Then, depending on the pest, you can arm yourself with soap or hot-pepper sprays, horticultural oil, or Bacillus thuringiensis, a naturally occurring bacterium that disrupts the digestion of caterpillars and other leaf-eaters.
Surrender. As we said, insects attack plants under stress. Do you have enough healthy plants to spare the sickly ones? Can you restore sickly plants to robust health so they can resist insect attack? If not, let the pests do their worst, then watch as their predators flock to your garden and protect your healthy plants.
Key To Success: Check the undersides of leaves when applying organic pest control—insects often hide out of sight.