The goal of the project was to monitor the European forests for the presence of decline associated with the presence of phytoplasmas and to monitor their insect vectors or putative vectors. The project developed a network for the application of common existing or newly developed protocols for the monitoring and identification of phytoplasmas in the European forests and in the insects collected there. The outcome of the project broadened the knowledge on phytoplasma epidemiology, provided useful information about phytoplasma monitoring and detection/identification in forests to associated decline syndromes with phytoplasma presence, with special focus on phytoplasmas and insect vectors of exotic origin or never identified in European forest before. Wild areas surrounding grapevine, fruit trees and other cultivated crops were investigated in Austria, Bosnia & Herzegovina, France, Germany, Italy, Serbia and Slovenia. The insects and plant samples collected produced a preliminary picture of the presence and diversity of phytoplasma in these agroecosystems.

Several diverse phytoplasmas were identified in Scaphoideus titanus, the insect vector of grapevine “flavescence dorée”. Of these, only ‘Candidatus Phytoplasma asteris’, was demonstrated to be transmitted to plant species, however the ability of S. titanus to transmit the other phytoplasmas should be studied more thoroughly. In Italy Anaplotettix fuscovenosus, Arboridia ribauti,Euscelis incisus, Hyalestes obsoletus, Neoaliturus fenestratus, Orientus ishidae, Philaenus spumarius and Synophropsis lauri, were shown to host a number of diverse phytoplasmas (16SrI, 16SrII, 16SrIII, 16SrV, 16SrVI, 16SrVI, 16SrIX and 16SrXII-A) in restricted areas near vineyards in northern Italy while in central Italy Synophropsis spp was shown to harbour 16SrIX-E and E. incisus 16SrI-R phytoplasmas, respectively. The ability of these insects to vector the carried phytoplasmas was not experimentally demonstrated. 

Surveys conducted in various plant species collected in forest areas that surround cultivated fields provided information on the presence of phytoplasmas. In Germany about 5,000 elm trees of diverse species in forests were tested and 1/3 of the trees tested positive for the presence of ‘Candidatus Phytoplasma ulmi’. Phytoplasmas of the 16SrV group were identified in Italy, Germany, Slovenia, Serbia or Bosnia & Herzegovina in Ailanthus altissima, Alnus glutinosa, Alnus incana, Clematis vitalba, Fraxinus spp., Salix spp., Ulmus glabra, Ulmus laevis, and Ulmus minor. ‘Ca. P. solani’ was detected in Italy in Parthenocissus quinquefolia and Skimmia spp; phytoplasmas of the 16SrX group were detected in Convolvolus arvensis,Cirsium arvense and Celtis orientalis; in the latter species also 16SrIX phytoplasmas were identified. Moreover, phytoplasmas in group 16SrI were identified in Clematis vitalba, Morus spp., Rubus spp. and Sorghum halepense, in one case in mixed infection with 16SrX group phytoplasmas. In some cases, such as in Slovenia and in Serbia phytoplasmas were detected in cultivated plantations of Corylus avellana and in sugarbeet fields showing severe decline, respectively. The plants did not always show symptoms typical of phytoplasma presence. In Slovenia, the presence of ‘Ca. P. fragariae’ was confirmed in Acer campestre, Carpinus betulus, Crataegus laevigata, Fraxinus ornus, Quercus petraea and C. avellana. ‘Ca. P. fragariae’ was also detected in France in ash samples during the ash dieback survey. Extensive gallery of symptomatic forest species and a protocol for sampling plants were also provided to the participants to the network.