Planning for Insects

Some are your friends, some are your enemies. Bees, ladybugs, and praying mantises are cool, while tomato hornworms, cabbageworms, and aphids can give you nightmares. Insecticides tend to be pretty nonselective on one hand, but continually picking cabbage worms from your Swiss-cheese-looking cabbage gets old fast. What to do?
Here are some strategies common to many gardening books, old and new:
1. Judicious interplanting- the more diversity, the better. If you plant one large bed of cabbage or tomatoes, the moths flying over say "Nursery!" and lay hundreds of eggs for your pleasure. If you interplant strong-smelling herbs or flowers poisonous to their offspring, they get confused and may leave you alone. ATTRA.org has a paper about farmscaping that describes setting up hedgerows and breaks in fields at the commercial level to encourage beneficials (lots of nectaries for bees) and discourage the bad guys. We may not need huge hedgerows, but we can squeeze in some of the recommended plants.
2. Physical barriers. Something ate one of my tomato plants down to a nub year before last, twice. This past year I put tomato plants in the same place in cages. They were not touched. A cage or a bit of netting to keep the moths away at the right time could save you a lot of grief.
3. Use contact sprays for aphids and scale insects. "Organic" insecticidal soaps work on contact, so the residues won't bother your bees and predatory insects unless you actually spray them. And soaps wash off the plant easily, not harming you.
4. Spray as little as you can. Sometimes the bugs get to you, especially here in the South. People who say to just let the bugs have their share have never seen what Southern warm climates do to the insect population. Hit them if you must, but do it wisely, and only after trying other means of control. You'll be glad you did.