Cacopsylla melanoneura (Foerster): aestivation and overwintering habitats in Northwest Italy

Cacopsylla melanoneura (Foerster) is considered one of the most important vectors of ‘Candidatus Phytoplasma mali’, the phytoplasma associated with apple proliferation disease. In the last years several studies concerning the biology, the infectivity and the transmission activity of this psyllid highlighted the crucial role of the overwintered adults in the epidemiology of the disease. However very few information on the overwintering sites are available. The aestivation and overwintering habitats of C. melanoneura in Northwest Italy were studied. Samplings were carried out in conifer forests, chosen by following the direction of warm ascending currents. The altitudinal distribution of the psyllid as well as the shelter plants were investigated. Adults of C. melanoneura were collected on Abies alba (Miller), Picea abies (L.), Pinus sylvestris (L.) and Larix decidua (Miller) predominantly at an altitude range between 1,350 and 1,650 m a.s.l. It was possible in this way for the first time to follow the whole life cycle of C. melanoneura throughout the year.