How to remove spamassassin from amavisd

[Stephen Davies]

There is no mention that I can find in my amavisd configuration of 
spamassassin but my mail log is full of messages like:
Dec 13 16:30:16 mustang amavis[178016]: initializing Mail::SpamAssassin (0)
Dec 13 16:30:18 mustang amavis[178016]: SpamControl: init_pre_fork on 
SpamAssassin done
Dec 13 16:30:18 mustang amavis[178016]: extra modules loaded after 
daemonizing/chrooting: Mail/DKIM/ARC/MessageSignature.pm, 
Mail/DKIM/ARC/Seal.pm, Mail/DKIM/ARC/Verifier.pm, 
Mail/SpamAssassin/Logger/Amavislog.pm, 
Mail/SpamAssassin/Plugin/DMARC.pm, Mail/SpamAssassin/Plugin/FreeMail.pm, 
Mail/SpamAssassin/Plugin/HashBL.pm, Mail/SpamAssassin/Plugin/SpamCop.pm, 
Mail/SpamAssassin/Plugin/WelcomeListSubject.pm, Net/Cmd.pm, 
Net/Config.pm, Net/SMTP.pm

How can I stop this?

Cheers and thanks,
Stephen