NEW EVIDENCES OF THE HIGH SENSITIVITY OF MALUS DAWSONIANA TO APPLE PROLIFERATION DISEASE AND OF ITS VALUE FOR TESTING APPLE TREES

Looking for indicators of apple proliferation disease among 70 species of genus Malus, we noticed that M. Dawsoniana was remarkable by its reactions.
Inoculated directly in June on the scion this species develops a leaf reddening during the following autumn and a bark splitting and scaling during the next spring.
Later the scion dies and the apple rootstock gives suckers ended by witches brooms.

In double budding the reaction is obvious shortly after budbreak.
The scion stops its growth in late spring when it is 20 to 50 cm long and dies.
This result is much quicker than with other indicators.

Several observations show that this reaction is independent from an unseen latent virus in apple proliferation sources and that this species is not affected by usual apple viruses.

IX International Symposium on Fruit Tree Virus Diseases

G. Morvan, C. Castelain

https://doi.org/10.17660/ActaHortic.1975.44.29