INVESTIGATIONS ON THE NEMATODE DISEASE OF 
CEREALS CAUSED BY TYLENCHUS TRITICI 1 
By R. W. Leukel 2 
Assistant Pathologist, Office of Cereal Investigations, Bureau of Plant Industry , United 
States Department of Agriculture 
INTRODUCTION 
The nematode disease of wheat, caused by Tylenchus tritici (Stein.) 
Bast. (25, s) 3 , has been known to be prevalent for many years in Europe, 
where at times it has caused severe losses. The discovery in 1918 that it 
was destructive in certain parts of the United States led the Office of 
Cereal Investigations of the Bureau of Plant Industry to begin a study 
of the trouble with a view to controlling or completely eradicating the 
disease. The history of the disease and a description of the causal 
organism, together with certain phases of its physiology, were given by 
Byars (6) in 1920. The purpose of the present publication is to present 
the results of the more recent studies of the disease, including a detailed 
description of the common symptoms. 
COMMON NAME 
The nematode disease of cereals, caused by Tylenchus tritici , has been 
given various names in the countries where it has been observed. In 
Germany, owing to the similarity of the galls 4 to seeds of cockle, it is 
called “Radekrankheit” (cockle disease), and on account of the gnarled 
appearance of infected plants, it is also called “ Gichtkrankheit” (gout 
disease). In France it was confused for a long time with bunt or stinking 
smut and therefore referred to as “bl£ nielle.” In England, according to 
Ormerod (79), the disease has been called “purples,” owing to the purple 
tint of the galls at a certain stage of their development. It is known 
there also as cockles, ear cockle, and false ergot. In the United States the 
disease is known by various names, among which the most common are 
eelworm or nematode disease, cockle wheat, hard smut, and nematode, 
gall. The name nematode disease is used in this publication. 
GEOGRAPHICAL DISTRIBUTION 
The nematode disease of wheat is easily spread long distances by means 
of the galls mixed in the seed wheat. As a result, its distribution is almost 
world-wide. Sorauer (24, p. 26-30) states that it occurs in France, 
1 Received for publication Mardi 11, 1924. The major portion of the investigations herein reported was 
conducted at the Arlington Experiment Farm, Rosslyn, Va. The rotation studies were conducted on the 
farms of W. S. Finnell, Morrisville, Va., and j. E. Riffee, Woodstock, Va., whose generous cooperation 
together with that of B. A. Warriner, county agent, Woodstock, Va., assisted greatly in making this phase, 
of the investigations possible. A considerable portion of the research was conducted at Madison, Wis., in 
cooperation with the Wisconsin Agricultural Experiment Station. 
2 The writer wishes especially to express his appreciation for the assistance in various ways of Dr. L. 
P. Byars, formerly Pathologist, Office of Cotton, Truck and Forage Crop Disease Investigations .through 
the early stages of the investigation, and to Dr. A. G. Johnson for the many helpful suggestions and 
other valuable assistance rendered throughout the progress of the studies and in the preparation of the 
manuscript. 
8 Reference is made by number (italic) to “ literature cited,” pp. 954-955- 
4 Throughout this paper the word galls will be used to designate the common nematode galls found in 
wheat infected by Tylenchus tritici . 
Journal of Agricultural Research, 
Washington, D. C. 
(925) 
Vol. XXVII, No. 11 
Mar. 22, 1924 
Key No. G— 406 
85607—24-3 
