3.1. Field methods
In general, bees do not show symptoms that are reliable indicators of mite infestation. Tracheal mites affect the overwintering capability of bee colonies and have been associated with bees displaying disjointed wings (called ‘K-wing’) or crawling on the ground near hives. Crawling bees are only apparent during winter or early spring months, particularly when HBTM infestations are very high. With the widespread distribution of nosemosis (see Fries et al., 2012) and some viral infections which may cause similar symptoms (de Miranda et al., 2013), the presence of crawlers in front of colonies should not be used as a reliable indicator of HBTM infestation (Bailey, 1961; Bailey & Ball, 1991).
The only way to identify HBTM is to physically examine honey bees for mites. This section describes several sampling techniques to look for mites inside bees.