I have notices move and more visits from semalt crawlers and now that clients start to notice it in their stats it has become a nuisance. Putting this code at the bottom of the WordPress .htaccess file should help. It has tow other spambots I noticed on other client sites. savetubevide and kambasoft you can add others as need be.
# Stop spambots RewriteCond %{HTTP_REFERER} ^http://.*semalt\.com [NC,OR] RewriteCond %{HTTP_REFERER} ^http://.*kambasoft\.com [NC,OR] RewriteCond %{HTTP_REFERER} ^http://.*savetubevideo\.com [NC] RewriteRule (.*) http://www.semalt.com [R=301,L] SetEnvIfNoCase Referer semalt.com spammer=yes SetEnvIfNoCase Referer kambasoft.com spammer=yes SetEnvIfNoCase Referer savetubevideo.com spammer=yes Order allow,deny Allow from all Deny from env=spammer