Fall for a harvester (7)
I believe the answer is:
cropper
I believe this clue is a double definition.
'fall' is the first definition.
(I have seen 'Heavy fall' mean 'cropper' so perhaps 'fall' could also mean 'cropper')
'a harvester' is the second definition.
(thesaurus)
'for' is the link.
(Other definitions for cropper that I've seen before include "Disastrous mistake or fall" , "Come a --, suffer disaster" , "Heavy fall" , "failure" .)