There are different methods/products to control different insect pests so the first order of business is to identify the problem. Inspect the plants closely, especially very early in the morning or just at dusk......many insects are nocturnal in their habits. You can then post photos of the insects themselves or the damage they cause (best place is Garden Clinic forum) to get an identfication and recommended treatment. Often it is just a matter of using row covers to prevent flying insects from laying the eggs that will turn into the insect/larvae that feed on the plants.

For an edible garden, you want to be very sure what you are dealing with before you start spraying any insecticides or other potentially harmful pesticides on plants you intend to eat.

Agree with gardengal...identification of the culprits is essential for effective, responsible care of our gardens, especially the edibles. I will also add that the use of broad spectrum pesticides will cause a reduction of the beneficials that help us enormously in the garden.

We will be happy to help you with the ID of any critter you find in your garden and suggest ways to encourage the good guys while reducing the bad.

I suggest that you utilize the Garden Clinic forum, as well as the Vegetable Gardening forum for further questions. I wish that I could recommend the Organic Gardening forum but I feel that it has become an unfriendly place for useful information.