A plant initially concealed a pest (5)

I believe the answer is:

aphid

'a pest' is the definition.
(aphid is a type of pest)

'a plant initially concealed' is the wordplay.
'initially' says to take the initial letters.
'concealed' becomes 'hid' ('hide' can be a synonym of 'conceal').
The initial letter of 'plant' is 'p'.
'a'+'p'+'hid'='APHID'

(Other definitions for aphid that I've seen before include "Garden bug" , "Small insect like greenfly" , "Blackfly or greenfly" , "Plant louse" , "Fly" .)

I've seen this clue in The Daily Express.

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