Notes on wicked plague (7)

I believe the answer is:

bedevil

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'plague' is the definition.
(I know this)

'notes on wicked' is the wordplay.
'notes on' becomes 'bed' (I can't explain this - if you can you should give a lot more credence to this answer).
'wicked' becomes 'evil' (associated in meaning).
'bed'+'evil'='BEDEVIL'

Can you help me to learn more?

(Other definitions for bedevil that I've seen before include "Worry, harass" , "Dog" , "Afflict" , "Cause continual difficulties" , "Torture" .)

I've seen this clue in The Daily Express.

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