Crossword Genius

A Greek character’s a pest (5)

Ross

I believe the answer is:

aphis

'a pest' is the definition.
(I've seen this before)

'a greek character's' is the wordplay.
'greek character's' becomes 'phis' (letter from the Greek alphabet).
'a'+'phis'='APHIS'

(Other definitions for aphis that I've seen before include "Plant louse" , "Small insect" , "sucker?" , "Sap-sucking garden pest" , "Greenfly" .)

I've seen this clue in The Times.
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