Spamed by Arpwatch Notification : Cron

[Bigozz]

Hi All

After installing Arpwatch every 15 min I am sent an email from my Firewall with the following

X-Cron-Env: <SHELL=/bin/sh>
X-Cron-Env: <PATH=/etc:/bin:/sbin:/usr/bin:/usr/sbin>
X-Cron-Env: <HOME=/root>
X-Cron-Env: <LOGNAME=root>
X-Cron-Env: <USER=root>

0 addresses deleted.

Is there any way to disable this ?