About Lesson
Based on population presence:
i. Key pest: Pests whose populations are always above the damage threshold are called keypestst or regular pests. They need constant watch and control. E. g. fruit fly, aphid, cotton ball worm.
ii. Occasional pests: these are those pests whose populations remain low and insignificant for a long period. They increase to damaging levels due to the possibility of favorable climatic conditions or depletion of natural enemies. E. g. locust
iii. Potential pest: potential pests are those that might be highly injurious if not kept under control by natural enemies like red spider mites.