Plague insects (7)
I believe the answer is:
locusts
'plague insects' is the definition.
'locusts' can be an answer for 'insects' (locust is a kind of insect). I also know that 'plague' relates to this answer.
This is the entire clue.
(Other definitions for locusts that I've seen before include "Destructive grasshoppers" , "can be a plague" , "Grasshoppers of warm regions" , "Strippers" .)