ENDROT OF CRANBERRIES 1 
By C. L. Shear, 
Plant Pathologist , Fruit Disease Investigations, Bureau of Plant Industry, United States 
Department of Agriculture 
INTRODUCTION 
In the writer's early studies of diseases of the cranberry (Oxycoccus 
macrocarpus) occasional cultures of an undetermined organism of a rather 
striking and characteristic color appeared. These cultures, however, failed 
to produce spores, and their identity was not determined at the time. 
Since beginning cooperative experiments with the Massachusetts Agri¬ 
cultural Experiment Station on Cape Cod, this organism has been found 
to be the most frequent fungus causing a rot in Late Howe berries from 
the experimental plots and checks on the Massachusetts State Cranberry 
Experiment Station bog at East Wareham. The fungus has also been 
frequently found in diseased berries, especially the Late Howe, from 
Maine, New Jersey, Michigan, Wisconsin, Washington, and Oregon. 
Although this rot has been found thus far most abundantly in the Late 
Howe cranberry, further investigation may show that it is equally serious 
with some other varieties. It has been isolated from the following varie¬ 
ties: Bennett Jumbo, Cape Cod Beauty, Early Black, Early Ohio, Mathews, 
McParlin, Perry Red, Prolific, Searles Jumbo, Selected Howe, Vose 
Pride, and several unknown varieties. It no doubt occurs in others that 
have not yet been examined. Sufficient observations have not been 
made at present to determine the relative susceptibility of these varieties. 
It is evident from the amount of this rot found in various samples of 
fruit from all the cranberry-growing sections the past two or three 
years that it is the cause of much loss. Whether the recent increase of 
this rot indicates that the disease is becoming more serious or has only 
appeared more frequently the past year or two on account of unusually 
favorable conditions for its development and distribution is not known. 
1 Grateful acknowledgment is due Miss A. M. Beckwith and Mr. Bert A. Rudolph, of the Bureau of 
Plant Industry, for assistance in making cultures and sections of the fungus, and to Dr. H. J. Franklin, of 
the Massachusetts State Cranberry Experiment Station, who carried out the spraying experiments in 
Massachusetts. 
Journal of Agricultural Research, 
Washington, D. C. 
ka 
(3S) 
Vol. XI, No. 2 
Oct. 8, 1917 
Key No. G—122 
