The project aimed to provide new knowledge of the epidemiology and diagnosis of Potato spindle tuber viroid (PSTVd), Citrus exocortis viroid (CEVd), Columnea latent viroid (CLVd), Chrysanthemum stunt viroid (CSVd), Tomato apical stunt viroid (TASVd) and Tomato chlorotic dwarf viroid (TCDVd) with major efforts targeting the risk of transmission of pospiviroids from ornamental plants to crops of tomato and potato and the development and validation of diagnostic laboratory manuals tobe presented to national and EC plant health authorities for surveillance and seedt esting purposes.To address these challenges the following activities were carried out:

-Surveying for new ‘natural’ host plants of the six targeted pospiviroids and investigation of host-pospiviroid interactions

-Investigation of possible transmission pathways that might spread pospiviroids from ornamental plants to crops

-Development of diagnostic RT-PCR-based assays for pospiviroids and validation of them by ringtesting

-Development of reliable assays for the detection of PSTVd in tomato seeds