A low level of pests must survive in order to maintain a population of their natural enemies. Inspect the plants for insect and disease damage. Find out what is living on the underside of the leaves. Many insects, such as ladybugs and praying mantises, are beneficial. Only a relatively small number of species are harmful.
Plants can tolerate some insect damage without significant loss to yield or aesthetics.
Good gardening is based on understanding nature's interactions. At the first sight of an insect, weed or disease, stay calm. Do not run for the sprayer or duster . If so, use the least toxic method of control, e.g. pull the weed, remove the diseased leaf or squash the harmful insect. The more often garden chemicals are used, the greater the risk of endangering our health and the environment.