Spiders/Bots problem slow down my site

I recommend changing your wordpress login page from wp-login.php to something different.

Then, in your .htaccess set your wp-login.php page to be blocked, like this:

#prevents access to wp-login
    <Files wp-login.php>
    order allow,deny
    deny from all
    </Files>

you can google to see different ways to change your login page. It is not too difficult, and will reduce the bots to almost zero.

You can use .htaccess file to block bots with some UserAgent. Add following lines after “RewriteEngine on” :

RewriteCond %{HTTP_USER_AGENT} Purebot [NC,OR] RewriteCond %{HTTP_USER_AGENT} DotBot [NC,OR] RewriteCond %{HTTP_USER_AGENT} Ezooms [NC,OR] RewriteCond %{HTTP_USER_AGENT} Robot [NC,OR] RewriteCond %{HTTP_USER_AGENT} ichiro [NC,OR] RewriteCond %{HTTP_USER_AGENT} VoilaBot [NC,OR] RewriteCond %{HTTP_USER_AGENT} ReGet [NC,OR] RewriteCond %{HTTP_USER_AGENT} Rankur [NC,OR] RewriteCond %{HTTP_USER_AGENT} cmsworldmap [NC,OR] RewriteCond %{HTTP_USER_AGENT} libwww-perl [NC,OR] RewriteCond %{HTTP_USER_AGENT} SurveyBot [NC,OR] RewriteCond %{HTTP_USER_AGENT} RadioClicker [NC,OR] RewriteCond %{HTTP_USER_AGENT} Embedly [NC,OR] RewriteCond %{HTTP_USER_AGENT} TweetmemeBot [NC,OR] RewriteCond %{HTTP_USER_AGENT} discobot [NC,OR] RewriteCond %{HTTP_USER_AGENT} AhrefsBot [NC,OR] RewriteCond %{HTTP_USER_AGENT} SearchBot [NC,OR] RewriteCond %{HTTP_USER_AGENT} LinkpadBot [NC,OR] RewriteCond %{HTTP_USER_AGENT} bingbot [NC,OR] RewriteCond %{HTTP_USER_AGENT} SISTRIX [NC,OR] RewriteCond %{HTTP_USER_AGENT} Flexum [NC,OR] RewriteCond %{HTTP_USER_AGENT} BLEXbot [NC,OR] RewriteCond %{HTTP_USER_AGENT} siteexplorer [NC,OR] RewriteCond %{HTTP_USER_AGENT} kmbot RewriteRule ^.* - [F,L]