Host organs attacked by bacterial canker of stone fruits

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Introduction

The most destructive and widespread phase of bacterial canker in Prunus is limb cankers. The organism also attacks leaves, blossoms, fruit, fruit stems, green shoots, and buds. In an earlier article ⁽¹⁾,4 comparatively little was said concerning the development of these last-named phases of the disease during epidemics. As later observations show, certain infected host organs are important, both from a crop loss standpoint, and from the standpoint of avenues through which the bacteria enter the tree. These infected organs are oversummering sources of the bacteria as well.

British workers are giving considerable attention to a bacteriosis of plums ⁽⁴⁾ and cherries ⁽⁵⁾. Since one of the organisms associated with this disease resembles that of the California disease,5 the present paper also supplements earlier published ⁽¹⁾, ⁽²⁾, ⁽³⁾ material.

Proof of the Pathogenicity of Cultures from Different Host Organs.—Isolations at different times and from material collected in different localities yielded a. number of cultures. Inoculation and reisolation of certain of these cultures proved their pathogenicity to trees of plums, cherries, apricots, and peaches. In order, however to compare representative cultures from the various host organs more directly, extensive inoculations were made into cherry trees of the variety Bing.