Occurrence of Cherry virus A in the UK

Cherry virus A, a recently described member of the genus Capillovirus, was first reported in Prunus cerasus (Jelkmann, 1995). It is widespread in both Germany and Canada (James and Jelkmann, 1998; Eastwell and Bernardy, 1998). In the autumn, leaf and bark material were collected from 16 cherry trees of different UK origin growing at HRI-East Malling. RNA was extracted from these samples using a modified protocol based upon the Qiagen RNeasy kit (MacKenzie et al., 1997). RT-PCR detection of CVA was carried out according to James and Jelkmann (1998), except that the addition of Extender â„¢ PCR additive (Stratagene) was not necessary for successful amplification using primer CVA1 (James and Jelkmann, 1998) in combination with a newly designed primer CVA3.

CVA was found in leaf and bark material taken from 15 of the 16 sweet cherry trees. This is the first record of (i) the presence of CVA in the UK and (ii) the ability to detect CVA in dormant material. No data are available on the impact of CVA on fruit yield from sweet cherry orchards, yet it appears to be ubiquitious in the UK. CVA is graft transmissible and the only tree that tested negative for CVA was one grown from seed. CVA may not cause disease in these trees, but it is possibly deleterious as a synergist necessary for disease development. This work provides a starting point for research on the occurrence of the virus in UK planting material and its possible involvement in the aetiology of cherry diseases.