NON-IDENTITY OF THE CAUSAL AGENT OF STEM GROOVES IN PYRONIA VEITCHII WITH APPLE AND PEAR LATENT VIRUSES AND VIRUS-LIKE AGENTS ALREADY DESCRIBED

Pyronia veitchii reacts with different symptoms to the inoculation with some apple and pear viruses or virus-like agents.
Dents and grooves on the stem of this indicator are caused by a graft-transmissible agent latent in pear.
The relationship of this Pyronia stem grooves agent (PSGA) to well-known apple and pear latent viruses and virus-like agents was tested in graft-transmission experiments.
PSGA infected apple indicators without inciting any diagnostic symptoms, while Quince C 7/1, which had been reported as an indicator for some latent viruses and virus-like agents of pear, was proved to be not susceptible for PSGA. No stem grooves were induced in P. veitchii by graft-transmissible agents which cause symptoms in common apple virus indicators.
For these reasons, PSGA is not identical with the known latent viruses and virus-like agents of apple and pear.
Furthermore no correlation exists between an infection with pear decline and the occurrence of PSGA. Therefore P. veitchii should be withdrawn as an indicator for pear decline.

XIII International Symposium on Fruit Tree Virus Diseases

L. Kunze

https://doi.org/10.17660/ActaHortic.1986.193.10