Discovered novel scheme must be exploitation (7)
I believe the answer is:
overuse
'exploitation' is the definition.
(overuse is a kind of exploitation)
'discovered novel scheme' is the wordplay.
'discovered' says to take the centre.
'scheme' becomes 'ruse'.
The middle of 'novel' is 'ove'.
'ove'+'ruse'='OVERUSE'
'must be' acts as a link.
(Other definitions for overuse that I've seen before include "Excessive utilisation" , "Employ too much" , "Excessive consumption" , "why injury may occur" , "Excessive employment" .)