Critic to ban mechanisation in farming? (9)

I believe the answer is:
detractor
'critic' is the definition.
(I've seen this before)
'ban mechanisation in farming?' is the wordplay.
I cannot really understand how this works, but
'farming?' could be 'act' (farming is a kind of act) and 'act' is present in the answer.
This explanation may well be incorrect...
'to' is the link.
Can you help me to learn more?
(Other definitions for detractor that I've seen before include "Slighter" , "Critic" , "One belittling" , "one runs people down" , "One disparages or belittles" .)
