WALNUT BLIGHT IN THE EASTERN UNITED STATES. 3 



loss of young nuts. His paper gives a number of the characteristics 

 of the organism in pure culture, and his work has subsequently been 

 corroborated by Clayton O. Smith, of the Whittier Station in Cali- 

 fornia, and the writer, in the eastern United States. Pierce pro- 

 posed the term " bacteriosis " as being a suggestive name for the 

 disease, though by growers the malady is commonly known and 

 spoken of as walnut blight, which may be considered its common 

 name. The disease-producing organism is now known as Bacterium 

 juglandis (Pierce) Erw. Smith. 1 Since the publication of Pierce's 

 paper reports by other writers have appeared from time to time, 

 the most valuable contribution being Bulletin No. 231 of the Cal- 

 ifornia Agricultural Experiment Station. 2 The work reported in this 

 paper, which extended over a period of some years, largely con- 

 firmed Pierce's studies and greatly augmented the existing knowl- 

 edge of the disease-producing organism and its relation to its host. 



A brief quotation will serve to indicate the seriousness with which 

 this disease is regarded on the Pacific coast and the gravity with 

 which it should be considered by present and prospective growers 

 elsewhere. 



This is by far the most important trouble affecting the walnut in California. 

 So serious has been this disease that the loss of a large portion of the crop has 

 in some cases been charged to this source, legislatures have made special ap- 

 propriations for its investigation, and the growers have offered a large reward 

 for a practical remedy. 



At the same time the losses directly attributable to blight have been extremely 

 large. One significant fact in this connection is that while the walnut acreage 

 in southern California has multiplied many times during the past decade 

 (1902-1912), the total walnut crop has increased very little during this time. 



This, loss or failure of the crop to increase has not been entirely attributable 

 to blight, yet it has certainly been due to the disease much more than to any 

 other one factor.* 



Until a few years ago walnut bacteriosis had been definitely known 

 to occur only on the Pacific coast and in New Zealand. In 1913 

 Waite 4 reported the disease as occurring in the Eastern States. 

 He stated: 



The California walnut bacteriosis has turned up at various points in the 

 East. The twig-blight form of this disease is also prevalent in various States. 

 The walnut blight, or bacteriosis, is therefore to be figured with in planting the 

 Persian walnut in the East. ... It occurs in Texas and Louisiana, and I 

 think we have it in or near Buffalo, N. Y., and in New Jersey, so if I were 



1 Smith, E. F. Bacteria in Relation to Plant Diseases, v. 1, p. 171. Washington, 

 D, C. (Carnegie Inst., Washington, Pub. 27.> 



a Smith, R. E., Smith, C. O., and Ramsey, H. J. Walnut culture in California. Walnut 

 blight. Cal. Agr. Exp. Sta. Bui. 231, p. 113-398, 96 fig. 1912. 



* Smith, R. E., Smith, C. O., and Ramsey, H. J. Op. cit. 



* Waite, M. B. The diseases of nut trees. In Rept. Proc. 4th Ann. Meeting, Northern 

 Nut Growers' Assoc, 1913. p. 56. 1914. 



