UNITED STATES DEPARTMENT OF AGRICULTURE 
DEPARTMENT BULLETIN No. 1229 
Washington, D. C. T March 1, 1924 
THE STEM NEMATODE TYLENCHUS DIPSACI ON WILD HOSTS IN THE 
NORTHWEST. 
By G. H. Godfrey, Pathologist, Office of Cotton, Truck, and Forage Crop 
Disease Investigations, Bureau of Plant Industry, and M. B. McKay. Asso- 
ciate Pathologist, Oregon Agricultural Experiment Station. 
Page. 
Introduction 1 
Symptoms 1 
The causal organism 2 
Distribution 2 
Apparent independence of the two 
hosts 3 
Relation to environment 5 
CONTENTS. 
Page. 
Origin and dissemination of the 
disease 
Tnoculation experiments 
Economic significance 
Summary 
Literature cited 
INTRODUCTION. 
Attention has been called several times to the occurrence of the 
stem and bulb infesting nematode Tylenchus dipsaci Kiihn (Tylen- 
chus devaMatrix in most of the European literature) on various 
hosts in America. Byars (I) 1 mentioned its occurrence on hyacinth- 
Smith (9) and Byars (2) reported diseases in red clover and straw- 
berry due to the organism. McKay dealt more at length with the 
disease in strawberry (5) and later reported its occurrence on alfalfa 
(6) and wild strawberry, Frag aria cMJoensis (7). Godfrey {$) 
mentioned its occurrence on all the known hosts in America and 
briefly described the symptoms. This paper deals with the wide 
occurrence of the pathogen on the wild strawberry and reports an 
additional host, the false dandelion, Hypochaeris radicata. The dis- 
covery of the disease on this plant was made by Prof. H. P. Barss 
and the junior writer together, at Newport, Oreg., in June, 1922. 
H. radicata is listed by Massalongo (4, p. 8) as being subject to a 
nematode gall referred to as a " Helminthocecidium," which, judging 
from the illustration, is clearly the same as the one discussed here, 
SYMPTOMS. 
The symptoms of the disease on the wild strawberry (PL I, A, Z>\ 
and C) are in every respect the same as on the cultivated. Swellings 
1 The serial numbers (italic) refer to "Literature cited" at the end oif this bulletin. 
71560°— 24 
