2 BULLETIN 611, U. S. DEPARTMENT OF AGRICULTURE. 
cializing in the growing of young trees for general planting. These 
facts, together with the increasing volume of correspondence re- 
ceived by the Department of Agriculture relative to walnut diseases 
and the known occurrence of the walnut blight, or bacteriosis, in the 
eastern United States, make it desirable to publish at this time a 
resume of the history of this disease and its present status in the 
section specified, to the end that difficulties and disappointments 
may be avoided. 
Commercial walnut growing in the United States may be said to 
have had its origin on the Pacific coast. At present the principal 
production of Persian walnuts in this country is from a few counties 
in southern California, although within recent years there has 
been extensive planting in the San Joaquin Valley, the Sacra- 
mento Valley and adjacent valleys of northern California, and in 
the Willamette Valley of western Oregon. To a considerable extent 
this walnut is now being planted by amateurs and experimenters in 
other States, especially Arizona and New Mexico. As a result of 
this situation, systematic studies of the species and its varieties, its 
cultural requirements, diseases, and insect pests have largely been 
confined to the West, and except as analogies can be drawn there is 
little in agricultural literature that will be of assistance to a prospec- 
tive grower in the eastern United States. 
During the seasons of 1910, 1911, and 1914 specimens of diseased 
nuts were received by the Bureau of Plant Industry from points in 
Maryland, Louisiana, Pennsylvania, Virginia, and Delaware and 
determined by Mr. M. B. Waite, Pathologist in charge of the Office 
of Fruit-Disease Investigations, to be affected with the so-called 
walnut blight, or bacteriosis. During the summer of 1916 an effort 
was made by the writer to determine the extent of the occur- 
rence and the seriousness of this trouble in the eastern United 
States, as it appeared to be the most serious disease with which the 
industry now has to contend in this part of the country. Blighted 
nuts were found at practically all points at which bearing walnut 
trees were examined, and reports from other sections indicate that 
the presence of this disease is more or less general in the entire, 
eastern district. 
HISTORY OF WALNUT BLIGHT. 
In 1901 Pierce * reported a walnut disease due to a bacterium which 
had at that time become established in the seedling orchards of 
southern California. He stated that it was highly pathogenic on 
young nuts, leaves, and tender twigs and frequently caused serious 
i Pierce, N. B. Walnut bacteriosis. In Dot. Gas., ▼. 31, no. 4, p. 272-273. 1901. 
