UNITED STATES DEPARTMENT OF AGRICULTURE 
BULLETIN No. 444 { 
Contribution from the Bureau of Plant Industry >i_~ 
WM. A. TAYLOR, Chief JU&'^fU 
Washington, D. C. PROFESSIONAL PAPER November 25, 1916 
FALSE BLOSSOM OF THE CULTIVATED CRANBERRY. 
By 0. L. Shear, Pathologist, Fruit-Disease Investigations. 
CONTENTS. 
Introduction - - 1 
Description of false blossom 1 
Origin and distribution 3 
Economic importance 4 
Page. 
Cause 4 
Control 5 
Summary 5 
Literature cited 7 
INTRODUCTION. 
For a number of years past an abnormal development of vines of 
the cranberry (Oxycoccus macrocarpus) has caused considerable loss 
in cranberry marshes, especially in the district about Grand Rapids, 
Wis. The trouble is commonly called false blossom by the growers. 
Since this term is so generally used in Wisconsin and is somewhat 
applicable to the disease, it is probably best to adopt it as the com- 
mon name. It should be explained, however, that a disease of an 
entirely different nature, caused by Exobasidium oxy cocci Host., has 
received the same name among Massachusetts growers. The name 
rose-bloom is proposed for this latter disease. 
DESCRIPTION OF FALSE BLOSSOM. 
The disease under consideration produces as one of its most con- 
'spicuous features a malformation or metamorphy of the floral organs. 
It was briefly described by the writer (10) 1 in 1911. In the simplest 
form of the trouble the flower pedicels become more or less erect 
instead of drooping and the calyx lobes become enlarged, greenish, 
and somewhat foliaceous. The petals become shortened, broadened, 
i The figures in parentheses refer to " Literature cited" at the end of the paper. 
Note.— This bulletin is of interest to plant pathologists and to cranberry growers, especially in the 
States of Massachusetts, New Jersey, Wisconsin, and the coastal regions of Oregon and Washington. 
>°— Bull. 444 16 
