UNITED STATES DEPARTMENT OF AGRICULTURE 



BULLETIN No. 444 i 



'^~' Contribution from the Bureau of Plant Industry ■^ 



WM. A. TAYLOR, Chief JXf^'^^U 



Washington, D. C. PROFESSIONAL PAPER November 25, 1916 



FALSE BLOSSOM OF THE CULTIVATED CRANBERRY. 



By C L. Sheak, Pathologist, Fruit-Disease Investigations. 



CONTENTS. 



Introduction 1 



Description of false blossom 1 



Origin and distribution 3 



Economic importance 4 



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 Exohasidium oxy cocci Rost., 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 describ(^d by the writer (10)' 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 onlargcnl, greenish, 

 and somewhat foliaccous. ITie petals become shortened, broadened, 



' The figures In parentheses refer to " Literature cited" at the end of the paper. 



Note.— This bulletin la of Interest to plant pathologists and to cranberry growers, especially In tho 

 States of Massachusetts, New Jersey, Wisconsin, and tho coastal regions of OroRon and Washington. 

 MOWi' -Bull. 444 10 



