Sometimes it makes sense to exclude a particular directory or a domain name if it is running an application like phpMyAdmin as modsecurity and will block SQL queries.

It is also better to exclude admin backends of CMS applications like WordPress.

To disable modsecurity for a complete VirtualHost place the following

<IfModule security2_module>
    SecRuleEngine Off
</IfModule>

inside the <VirtualHost> section.

For a particular directory:

<Directory "/var/www/wp-admin">
    <IfModule security2_module>
        SecRuleEngine Off
    </IfModule>
</Directory>

If you don't want to completely disable modsecurity, use the SecRuleRemoveById directive to remove a particular rule or rule chain by specifying its ID.

<LocationMatch "/wp-admin/update.php">
    <IfModule security2_module>
        SecRuleRemoveById 981173
    </IfModule>
</LocationMatch>