Measures taken to destroy pests (5)
I believe the answer is:
steps
'measures taken' is the definition.
(I've seen this before)
'destroy pests' is the wordplay.
'destroy' is an anagram indicator (I've seen this in other clues).
'pests' with letters rearranged gives 'STEPS'.
'to' is the link.
(Other definitions for steps that I've seen before include "Stairs; paces" , "Paces; measures" , "Footfalls" , "Small ladder" , "Buchan's 1915 novel has 39 of them" .)