Barrier methods of pest control consist of physically separating the pest from its food source. They are the most effective and health-safe way of dealing with a pest problem. The pest may be actually removed physically from the vicinity of the food plant, as in removing snails near young plants or picking caterpillars off cabbage; or the pest may be excluded by netting or by fencing. Scaring may be effective too.
Physical control does not interfere with natural control systems which is a major advantage. It may be more costly and time-consuming than chemical control but there are no residues to consider. The removal of old crops and debris that harbour pests is an important part of physical control, as is early digging to expose over-wintering pests to the weather, and to predators.
Suitable barrier methods of pest control are given for each kind of pest.