What are these logged events in /var/log/messages

[redhat at barendse.to (Remco Barendse)]

On Thu, 18 Aug 2005, Ignacio Vazquez-Abrams wrote:

> On Thu, 2005-08-18 at 08:52 +0200, Remco Barendse wrote:
>> Hi list!
>>
>> On all my 4.x boxes (didn't see this on 3.x) I get this in
>> /var/log/messages the whole day:
>>
>> Aug 17 04:02:05 weblinux1 crond(pam_unix)[32149]: session closed for
>> user root
>
>> Some boxes have up to 770 of these events per day
>
> Look in /etc/cron.*.
>

OK, so I guess that for every cron job that is run as root such an event 
is written to /var/log/messages? Strange that it doesn't report which 
cronjob it has processed, the report as it is now is rather useless for 
any use.

Can I disable those messages?