Monophagous Pests– are those insects which are known to feed on only a single species of plants. Tryporyza incertulus is a monophagous pest and attacks only on paddy plants.
Oligophagous Pests– are insects confine their feeding activity to plants belonging to one taxonomic group i.e., one family. A well known example is the cabbage butterfly.
Polyphagous Pests- insects feed on a variety of cultivated crop plants. Schistocerca gregaria, Locusta migratoria are polyphagous insect pests.