Novelist drops back knowing one's a pest (8)

I believe the answer is:

greenfly

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

'novelist drops back knowing' is the wordplay.
'novelist' becomes 'greene' (Graham Greene).
'drops back' means to remove the last letter (the back letter is removed).
'knowing' becomes 'fly'.
'greene' with its last letter removed is 'green'.
'green'+'fly'='GREENFLY'

'one's a' acts as a link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.

Can you help me to learn more?

(Other definitions for greenfly that I've seen before include "Pests" , "Common aphids" , "Common aphid" , "Garden pest" .)

I've seen this clue in The Guardian.

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