Shipworm produced by odd characters in The Green Party (6)
I believe the answer is:
teredo
'shipworm' is the definition.
(teredo is a kind of shipworm)
'odd characters in the green party' is the wordplay.
'odd characters in' indicates alternate letters (the letters at odd-numbered positions).
'party' becomes 'do' (do is a kind of party).
'the'+'green'='thegreen'
The alternating letters of 'thegreen' are 'tere'.
'tere'+'do'='TEREDO'
'produced by' is the link.
(Other definitions for teredo that I've seen before include "Boring marine worm" , "Marine mollusc that bores into ships" , "Shipworm - red toe (anag)" , "Boring mollusc" , "Marine mollusc that damages ships" .)