JOURNAL OF ACMamtAL RESEARCH 
Voe. XXVI Washington, D. C., October 13, 1923 No. 2 
A NEW TUMOR OF THE APRICOT 1 
By Amram Khazanoff 3 
College of Agriculture , University of California 
INTRODUCTION 
A peculiar disease manifesting itself in the formation of tumors, or 
galls, on the trunk and limbs of old apricot trees was investigated by 
the writer in California in 1916. While, as will be seen, the findings of 
that year do not amount to a complete knowledge of the disease, it has 
seemed desirable, in view of the writer's inability to follow the work to 
its completion, to publish the results thus far obtained, so that they 
may constitute a starting point for some other worker who may desire 
to investigate further this interesting disease. 
HISTORY AND DISTRIBUTION OF THE APRICOT GALL 
The apricot gall was not reported by growers until it had been in 
existence for a fairly long period of years. While nothing definite can 
be said concerning tie date of its first appearance, it seems to have been 
known in Santa Clara and Alameda Counties, Calif., for at least 15 years 
previous to these investigations. Its spread during those years was very 
slow. A marked progress, however, was noted, so one grower informed 
the writer, during the spring following the unusually wet winter of 1915, 
when as many as 60 trees became affected in an orchard where only 1 
diseased tree had been known to exist for the 12 previous years. At 
present the disease occurs in Alameda and Santa Clara Counties, especially 
around Hayward, San Jose, and Niles, extending also into San Benito 
County. In this region numerous cases have been observed both on 
isolated trees and on groups of trees forming diseased spots in the 
orchards. Recently several cases have been reported from Santa 
Cruz County, Calif., and apparently the same disease has been found on 
French prunes in Napa County. 
DESCRIPTION OF THE DISEASE 
New galls usually make their appearance during the moister part of 
the spring, in March or early April. Their period of growth coincides 
with the growing season of the tree. During their first season the galls 
do not, as a rule, become very prominent. They form eruptions reaching 
1 Accepted for publication May a, 1923. 
* Thanks are hereby given to Prof. R. E. Smith, Prof. W. T. Horne, and Prof. E. H. Smith, of the Divi¬ 
sion of Plant Pathology, University of California, for the kind interest they have taken in this work; to 
Mr. W. C. Mathews, of the Division of Scientific Illustration, for many valuable suggestions in connection 
with the illustration of this article; to Mr. T. C. Gorrie of Hayward, Calif., for facilities in connection with 
the field work on this disease; and to Miss Helen Czarnecki and Miss Edith Phillips for assistance as noted 
in the text. 
Journal of Agricultural Research, 
Washington, D. C. 
agv 
60373—23-1 
Vol. XXVI, No. s 
Oct. 13, 1923 
Key No. Calif.-36 
(45) 
