POTENTIAL PSYLLID VECTORS OF CANDIDATUS PHYTOPLASMA MALI AND CANDIDATUS PHYTOPLASMA PYRI IN TURKEY

Fruit tree diseases caused by phytoplasma have great economic effects on fruit production, especially in Europe. A major phytoplasma is ‘Candidatus Phytoplasma mali’, which causes apple proliferation (AP) disease mainly in cultured and wild forms of apple trees (Seemuller et al., 2011a); however, there has been a report of different hosts, including Prunus avium (L.) L., P. armeniaca L., and P.domestica L. (Mehle et al., 2007). ‘Ca. Phytoplasma pyri’ causes pear decline (PD) disease that is found mainly in cultured and wild forms of pear (Pyrus spp.) and quince (Cydonia oblonga Mill.) (Seemuller et al., 2011b). These phytoplasma are taxonomically classified into the 16SrX group (or AP-group) of phytoplasmas and constitute closely related subgroups (Seemuller and Schneider, 2004). Phytoplasmas are mainly spread by vegetative propagation or the grafting of infected plant material and phloem feeding insects, primarily leafhoppers, planthoppers and psyllids (Weintraub and Beanland, 2006). Only one genus of this last one, Cacopsylla spp., transmit AP-group phytoplasmas to pome and stone fruit trees. In apple orchards, ‘Ca. P. mali’ can be transmitted by two psyllid species. Cacopsylla (Thamnopsylla) picta (Foerster, 1848) (syn. C. costalis) has been reported main vector in Germany (Jarausch et al., 2003, 2011) and northern Italy (Frisinghelli et al., 2000; Carraro et al., 2008), while Cacopsylla (Thamnopsylla) melanoneura (Foerster, 1848) was identified as main vector in Aosta Valley (Tedeschi et al., 2002). C. picta is monophagous on Malus spp. and until now this species have been described only in Europe (Burckhardt, 1994; Ossiannilsson, 1992; Ouvrard, 2014) and Turkey (Klimaszewski and Lodos, 1977, 1979; Drohojowska and Burckhardt, 2014). C. melanoneura has a Palaearctic distribution and is oligophagous on Rosaceae, its principal host plant being a common shrub, hawthorn (Crataegus monogyna L.) (Ouvrard, 2014). In most of studied cases, both psyllid species are present in apple orchards (Jarausch et al., 2003; Delic et al., 2005; Carraro et al., 2008; Mattedi et al., 2008). Two others species living on hawthorn, Cacopsylla peregrina (Foerster, 1848) and Cacopsylla (Thamnopsylla) affinis (Low, 1880), were found able to harbor the phytoplasmas of the AP-group, in particular ‘Ca. P. mali’ (Tedeschi et al., 2009). Their transmission ability was not proven but this result highlights the potential role as vector of these psyllid species. In pear orchards, until recently, two psyllid species were known as vector of ‘Ca. P. pyri’. Cacopsylla (Hepatopsylla) pyricola (Foerster, 1848) has been reported for Great Britain (Davies et al., 1992) and North America (Jensen et al., 1964), while Cacopsylla (Hepatopsylla) pyri (Linne, 1758) was described as the vector in France (Lemoine 1984), Italy (Carraro et al., 1998a) and Spain (Garcia-Chapa et al., 2005). C. pyri is widespread in Europe, in the Caucasus, Georgia, the Middle Asia, including Turkey (Klimaszewski and Lodos, 1979; Burckhardt and Pak. J. Agri. Sci., Vol. 53(2), 383-392; 2016 ISSN (Print) 0552-9034, ISSN (Online) 2076-0906 DOI: 10.21162/PAKJAS/16.3804 http://www.pakjas.com.pk