Insecticide (9)
'insecticide' is the definition.
(I know that pyrethrum is a type of insecticide)
This is the entire clue.
(Another definition for pyrethrum that I've seen is " flower".)
(Other definitions for pyrethrin that I've seen before include "Extract from aromatic flowers" , "Compound" .)
'insecticide' is the definition.
(I know that Malathion is a type of insecticide)
This is all the clue.