CROWNWART OF ALFALFA CAUSED BY UROPHLYCTIS 



ALFALFAE 



By Fred Reuee Jones, Pathologist, and Charles DrechslEr, Assistant Patholo- 

 gist, Office of Cotton, Truck, and Forage Crop Disease Investigations, Bureau of Plant 

 Industry, United States Department of Agriculture 



INTRODUCTION 



When between the years 1909 and 1914 the so-called erownwart of 

 alfalfa was found scattered through several important alfalfa-growing 

 regions on the Pacific slope of the United States, much interest was 

 aroused. The earliest publication dealing with the disease in South 

 America indicated that it might become of considerable economic im- 

 portance. The fact that it had attained but limited distribution sug- 

 gested that prompt study might reveal the possibility of effective 

 measures against further spread as well as means of averting serious loss 

 in the regions already invaded. In 191 5 this interest formulated itself 

 in a petition 1 framed by the American Phytopathological Society 

 addressed to the United States Department of Agriculture calling atten- 

 tion to existing conditions and urging work upon this interstate problem. 

 In 1 91 7 it became one of the duties of the senior author to begin work 

 upon this disease. The junior author was associated with the work in 

 1919, making the field observations, giving especial consideration to the 

 taxonomy and morphology of the causal organism, and preparing all the 

 drawings. This paper is a report of the progress that has been made in 

 the study of this disease. 



THE DISEASE 



COMMON NAMES 



In the United States the disease is commonly know bv either of two 

 names, crowngall and erownwart. As will be shown later, the structure 

 of the diseased tissue is that of a true gall, and it was called such in the 

 earlier reports of its occurrence. Later the name erownwart was sug- 

 gested in order to distinguish the disease from the bacterial crowngall 

 caused by Pseudomonas tumefaciens , though it had not then been shown 

 that this disease occurs upon alfalfa in the field. Recently, however, 

 galls have been found by Mr. H. L. Westover on alfalfa in Arizona 

 which appear to be true crowngalls, though complete proof is lacking. 

 In view of the fact that a gall similar in appearance to that caused by 

 Urophlyctis alfalfae (Lagerh.) P. Magnus is found upon alfalfa, it is even 



1 Phytopathology, v. 5, no. 2, p. 130-131. 1915. 



Journal of Agricultural Research, Vol. XX, No. 4 



Washington, D. C Nov. 15, 1920 



V p Key No. G-209 



( 2 95) 



