ACZoom

The FAQ posting FAQ: is-it-possible-to-block-hosts-abusing-non-hosts-access-services-such-as-apache
has all the info needed. The pattern needed is this, though I have not tested it:

    "apache-file-not-found": r'\[client {HOST_IP}\] File does not exist: /home/phpMyAdmin',

But it may be better to use Apache configuration itself to quickly return appropriate response to queries for non-existent files.