Insect and pest infection is major cause of large scale destruction of crop plants and their products. Biochemical, morphological or physiological characteristics are used for insect pest resistance in host crop plants are:

• Hairy leaves in several plants are associated with resistance to insect pests. e.g., resistance against jassids in cotton and cereal leaf beetle in wheat.
• In wheat, solid stems lead to non - preference by the stem sawfly.
• Smooth leaved and nector - less cotton varieties do not attract boll worms.
• High aspartic acid, low nitrogen and sugar content in maize lead to resistance to maize stem borers.

Breeding methods for insect pest resistance involve the same steps as those for any other agronomic trait like yield or quality and are discussed earlier. Sources of resistance genes may be cultivated varieties, germplasm collections of the crop or wild relatives. Some insect pest resistance varieties produced by hybridisation and selection.