A ProMED-mail post
ProMED-mail is a program of the International Society for Infectious Diseases

June 29, 2004
From: European and Mediterranean Plant Protection Organisation (EPPO) Reporting Service 2004, No. 01 [edited]

Occurrence of potato spindle tuber pospiviroid (PSTVd) in tomato plants in Germany

The National Plant Protection Organisation (NPPO) of Germany recently informed the EPPO Secretariat of the first occurrence of potato spindle tuber pospiviroid (PSTVd - EPPO A2 list) in Germany (Nordrhein-Westfalen). A group of about 15 tomato plants, within a stand of about 1.25 hectares, showed typical symptoms, such as growth depression and leaf discoloration starting from the edge. The disease was identified as PSTVd by polymerase chain reaction (PCR). Measures were taken to eradicate the disease. It is assumed that the disease was introduced in imports of infected tomato transplants.

The declared status of PSTVd in Germany is: Single occurrence, eradicated.

Source: NPPO of Germany, 2004-01.

[In tomatoes, PSTVd symptoms develop slowly, often not becoming apparent until 4 or 5 weeks after infection. Infected plants become stunted and show "bunchy top" symptoms (crowded foliage, due to shortening of internodes, and occasional formation of spindly shoots). Leaf symptoms include yellowing and purpling as well as considerable leaf distortion including downward curling of the leaflets (epinasty), curling, and twisting (rugosity). Severe necrosis along the veins develops later in the lower and middle leaves, which eventually die. Younger leaves at the top of the plant remain but are reduced in size. Flowers are often aborted, and fruit ripening is erratic. Fruits becomes small and hard and can turn dark green. Overall yields can be significantly reduced.

Disease management basically depends on planting viroid-free transplants. Once PSTVd has been introduced onto a farm or nursery, it can be rapidly spread from plant to plant through the use of contaminated cutting tools and/or machinery, by handling, or simply by direct plant to plant contact. PSTVd can also be transmitted via infected pollen. To prevent the spread within growers' fields, good hygienic practices are necessary to prevent contact with potentially infected plants, and, to avoid subsequent spread of the viroid. Contaminated benches, tools, etc. should be disinfected. 2--3 per cent hypochlorite has been shown to be effective.

A useful reference:http://www.defra.gov.uk/planth/pestnote/pstv.htm - Mod.DH]