Drupal's .htaccess does not deny access to nodes
In your settings.php file you can add the following lines and upon recognition of an HTTP_REFERER Drupal will not deliver any page data.

if ($_SERVER['HTTP_REFERER'] == 'http://spamhost1.com') {
  exit;
}


You should consider looking into existing modules that block spam though.  Trying to manage this one URL at a time seems like a lot of work.