8 CAUSE AND NATURE OK CROWN-GALL 



result seems to depend upon whether the natural or the diseased 

 growth secures the ascendency early in the life of the tree, for 

 apricot trees have been taken up after 30 years of satisfactory 

 growth and bearing and found to have roots badly infested with 

 the knots." 



PUBLISHED ACCOUNTS RELATING TO CROWN-GALL. 



The writer's attention was first called to this disease in 1803, 

 when many observations were made in infested orchards in the 

 vSalt River Valley. As the result of these investigations, a prelim- 

 inary report was published.' In this report the disease was 

 described under the name of crown-knot. Attention was called 

 to the seriousness of the disease in the Salt River Valley. Some 

 of the more characteristic features regarding its development 

 were pointed out and possible corrective measures were given. 



Various names have been applied to these outgrowths by 

 different authors. Although Woodworth first used the term 

 crown-gall to designate the disease, he later used the term 

 crown-knot. :! Orchardists frequently speak of the disease under 

 the name of black-knot and root-knot, but as these names are 

 in common use to designate other well-known diseases and out- 

 growths they had best be discarded in speaking of this disease. 

 Erwin F. Smith, in writing regarding it in 1S94, also uses the 

 term crown-gall. 4 He, however, discusses these excrescences 

 or outgrowths on the stems and roots of plants under the general 

 title " Stem and Root Tumors." Bailey uses the name root- 

 galls in his publication regarding the swellings. 



So far as the writer is aware, all more recent publications on 

 the subject have been under the name crown-gall. As this 

 term is applicable to the disease and is not likely to be confus- 

 ing, it is adopted in this bulletin in preference to crown-knot 

 used by me in my previous writings on this subject. Although 

 public attention in the United States was first directed to this 

 disease in 1892, and then only in California, it has since been 

 recognized in nearly every fruit-growing region in this country. 

 The more important reports regarding it have appeared during 



2 Bull. Ariz. Agr'l Exp. Sta., 12 (1894). 

 3 Rept. Cal. Agr'l Exp. Sta. iS94-'95, 231. 

 4 Jour. Myc, VII, 376. (Field notes, 1892. 



