VIRUS INDUCED CHANGES IN THE GROWTH OF POME FRUIT TREES

The effect of several virus and microplasma-like infections on the growth, cropping and general behaviour of healthy apple and pear cultivars on several rootstocks was examined in four experiments over a number of years.

Pome fruit cultivars and rootstocks differed greatly in their sensitivity to the viruses; pears were usually less tolerant to infection than apples and no virus spread occurred in any of the experiments.

Many characteristics of the trees were changed by the viruses; most were reduced in vigour and trees were less uniform.
Some infections rendered the crop unsaleable or markedly reduced crop weight and fruit size.
In a few cultivars some infections increased fruit colour and improved the crop to trunk girth ratio.

Symposium on Clonal Variation in Apple and Pear

A.I. Campbell, T.R. Sparks

https://doi.org/10.17660/ActaHortic.1977.75.14