This article lists some of the mechanical and cultural methods used to reduce pests in the garden. Physical barriers placed around some plants control certain insects. Shields -Squares of carpet or tar paper fitted snugly around the stem of young cole crop seedlings will prevent maggot larva from reaching the roots. In biological control , pests are controlled by the introduction of predators, parasites or diseases. This is an area many gardeners are exploring.
Some biological controls are commercially available.
Tilling under crop debris in the fall destroys the habitat for many overwintering insects and plant diseases, thereby reducing their number the following year. Insects may be hand picked from the plant. This is one of the most practical methods, especially when the pests are large, easily seen and relatively inactive. For example, Colorado potato beetle can be controlled this way. Insects may be killed by placing them in a bucket of water containing powdered laundry detergent.