Scientific note: varroa mite eradication, the strange case of Gorgona Island

Varroa mites are vectors for several bee viruses contributing also to their diffusion worldwide (Martin 2001; Di Prisco et al. 2011; Cersini et al. 2013). The tripartite relationship among bees, mites, and viruses is thought to be responsible for the loss of a large amount of colonies (Highfield et al. 2009; Berthoud et al. 2010; Francis et al. 2013). Before the arrival of Varroa destructor , virus prevalence was lower (Martin et al. 2012). The mites have contributed to spread the viruses which could be correlated to the high number of mite-infested honey bee colony losses (Berthoud et al. 2010; Francis et al. 2013). Since the varroa mite arrival, control of varroosis has become necessary (Moritz et al. 2010). Such control is focused on the coexistence between honeybees and mites. A trial to eradicate the mite from isolated areas has not been successful. Experiments carried out to eradicate varroa mite by use of several coordinated treatments in Jersey, an island in the English Channel, did not succeed, showing how difficult it is to eradicate this ecto-parasite from an infested area (Sampson and Martin 1999). The aim of this study is to report the disappearance of varroa mite from the island of Gorgona (43° 26′ N; 9° 54′ E) following several treatments in a single apiary kept in complete isolation. Furthermore, after the varroa disappearance, the honeybee viral load has been analyzed. Gorgona Island has been chosen because it provides suitable conditions to guarantee continuous monitoring and isolation to avoid new reintroduction of bee pathogens and pests.