September 9, 2003
From: EPPO Reporting Service 2003, No. 7 [edited]

2003/100
Potato spindle tuber pospiviroid found in tomatoes in United Kingdom

The United Kingdom NPPO informed the EPPO Secretariat that an outbreak of Potato spindle tuber pospiviroid [PSTVd] (EPPO A2 list) was very recently discovered in a tomato production glasshouse in southeast England. Investigations are under way to ascertain its extent and the possible pathway for the introduction of the pathogen. Phytosanitary measures are also being designed to prevent any further spread of the pest and possibly eradicate it. More information will be provided in due course.

Source: NPPO of United Kingdom, 11 Jul 2003.

[This is the first confirmed instance of PSTVd infection in the UK. It had previously been reported from potato (France) and tomato (Netherlands). PSTVd can reduce yields by as much as 65 and 50% in potato and tomato, respectively. Other natural hosts include pepino (_Solanum muricatum_), avocado (_Persea americana_), and a range of solanaceous crops. Results of studies on several viroids including PSTVd and the Mexican papita viroid (MPVd), found in 1982 in symptomlessly infected _Solanum cardiophyllum_ in Aguascalientes state, suggest that MPVd may be the putative ancestor of crop viroids. PSTVd was reported in the 1930's to be transmitted by chewing insects (aphids, grasshoppers, flea beetles, tarnished plant bug, leaf beetle, and Colorado potato beetle). MPVd, present in symptomlessly infected solanaceous plants, may have been transferred by such insects to breeding plots and commercial potato crops. Reference <http://www.pnas.org/cgi/reprint/93/18/9397.pdf > - Mod.DH]