Viroids belonging to the genus Pospiviroid can cause severe symptoms in solanaceous crops including tomato and pepper, however, they often show no or only very mild symptoms in several solanaceous ornamental species. Some viroids are known to be seed transmitted and others are thought to be highly likely to be seed transmitted. Therefore, it is important to screen seed pre-planting.

For this package 1500 seeds are tested for Potato spindle tuber viroid (PSTVd), Tomato chlorotic dwarf viroid (TCDVd), Columnea latent viroid (only this test is accredited) and Tomato apical stunt viroid by real time RT-PCR (TaqMan). For the PSTVd and TCDVd testing seed will be tested by a single TaqMan assay that detects both PSTVd and TCDVd as well as isolates of Mexican papita viroid (MPVd) and Tomato planta macho viroid (TPMVd).

If the sample was positive, PCR and sequencing would be required to identify which viroid was present. There would be an additional charge for this testing – see ‘Identification and confirmation of pospiviroid seed positive test' , details below.

There would also be additional charges for testing the seed for other viroids (Pepper chat fruit viroid, Citrus exocortis viroid) – see 'Additional pospiviroid seed testing' below for further details.

Identification and confirmation of pospiviroid seed positive test

Additional pospiviroid seed testing

The CLVd TaqMan test is UKAS accredited. The other viroid tests are not currently UKAS accredited for seed testing.

A screen for a range of pospiviroids causing symptoms in protected indoor crops such as tomatoes and cucumbers.

When sending plant pathogens and invertebrate samples from outside England and Wales for testing please email the Crop health team (crophealth@fera.co.uk) who will issue you with the relevant Letter of Authority to ensure your samples are not delayed upon entry to the UK.