Apple proliferation (AP), pear decline (PD) and European stone fruit yellows (ESFY) are caused by ‘Candidatus Phytoplasma mali’, ‘Ca. P. pyri’ and ‘Ca. P. prunorum’, respectively. These are the main phytoplasma diseases on pome and stone fruit that cause severe diseases on commercial crops. The main goal of the APOPHYT project is to improve the understanding of the multitrophic interactions between plants – vectors – phytoplasmas in order to develop disease management strategies and finally to reduce the impact of phytoplasma diseases in Europe. The different work packages aim to deeper analyse parts of the multitrophic interactions: 1. Phytoplasma Is it possible to improve diagnostics and to develop more sensitive detection methods (WP5) ? Are phytoplasma present as latent infections in nuclear plantings and nurseries (WP2) ? How are phytoplasma distributed in Europe (WP2) ? What are the population dynamics and the diversity of AP strains within apple trees (WP3) ? Is it possible to evidence virulence differences of AP strains (WP3) ? 2. Host plant and plant – phytoplasma interactions What is influencing the disease development at different locations in Europe (WP4) ? How different climatic conditions influence symptom expressions (WP4) ? Can symptom expressions be linked with phytoplasma titre (WP4) ? 3. Vector and vector – host plant interactions Can all vectors be found at all location in Europe (WP6) ? What is the percentage of vectors infested with phytoplasma (WP6) ? What is the influence of host plants on vector behaviour (WP6) ?

Scientific report of the Euphresco funded project 'Evaluation of factors determining distribution, impact, detection and characterization of fruit tree phytoplasmoses' (APOPHYT)