The Field Guide to Honey Bee Diseases
Penn State University publication – free download
Web based disease identification resource http://healthybeeguide.com/disease_identification
 
 

With the infestation of hives in Italy in late 2014 with small hive beetle Aethina tumida – a little bit about the pest.
The beetle – of sub saharan origin was first identified in Calabria (the toe of Italy) on 11th September.  As an invasive pest it is notifiable.  The NBU have an advisory leaflet
An article on the beetle, its control and management is here – the best defence seems to be strong unstressed colonies
YouTube provides some interesting clips on techniques for catching the beetle.  Monitoring a hive can be achieved using panels of black corex (the sort of thing estate agent signs are made of these days.  Or they can be purchased from bee supply houses.