mrtg (pam) fills log in FC3

[Dennis Bjorklund]

In FC3 I get lots of messages in /var/log/messages like:

Dec 12 12:15:02 foo crond(pam_unix)[4529]: session closed for user root
Dec 12 12:20:01 foo crond(pam_unix)[4532]: session opened for user root by (uid=0)

I get these every fifth minute and it's mrtg that generates them. Is there
some simple way to stop these messages except by uninstalling mrtg?

-- 
/Dennis Björklund