



t 





CROWN-GALL OF ALFALFA 



O. T. Wilson 



(with plates vii-x) 



Introduction 



The crown-gall of alfalfa has been known in the United States 

 for only a few years, the first published record of its occurrence 

 in this country being in 1909. It was at that time observed in 

 California by Smith (32). Since then it has been reported from 

 Arizona (23), Oregon (26), and Utah (27). It is probable that 

 it also occurs in other western states. The disease has been known 

 somewhat longer in other countries. Patouillard and von 

 Lagerheim (28) in 1895 published the earliest record of its oc- 

 currence in connection with an outbreak in Ecuador. In 1902 

 Magnus (21) described the general features of the disease and 

 recorded its presence in Germany. It has also been reported 

 from England (29), and Italy, Sweden, and Switzerland (10). 



The lack of detailed information makes it difficult to estimate 

 the economic importance of the disease. Old and powerful stands 

 were killed in the fields of Ecuador (19). Magnus considered 

 the disease serious at Colmar in Alsace. Salmon (29) advised 

 strict precautions against its spread in England. In the United 

 States McCallum (23) reported the disease as serious but not 

 widely distributed in Arizona at the time of his observations. 



California. According 



many 



stroyed by the parasite in Oregon. In 191 5 resolutions were 

 adopted by the American Phytopathological Society (31) recogniz- 

 ing the serious possibilities of the disease and recommending its 

 investigation by the government. 



ie purpose 

 history of 



Material and methods 



Infected plants were secured from the vicinity of Medford, 

 Oregon. In the winter of 1913-1914 P. J. O'Gara sent specimens. 



Si] 



Botanical Gazette, vol. 70 



