Pest occur in a severe form in a region or locality at a particular season or time only.

Occasional pests, a close association with a particular crop is absent and they occur infrequently. Eg: Rice case worm. Persistent pests: Occur on a crop almost throughout the year. Eg: thrips on chilies. Sporadic pests: Occur on a few isolated localities. Eg: coconut slug caterpillar. Epidemic pest: Occur in a severe form in a region or locality at a particular season or time only. Eg: Rice hispa. Endemic pest: Occur regularly and confined mostly to a particular area or locality. Eg: Red hairy caterpillar in groundnut.