Dec. i7, 1917 
Bacterial-Blight of Barley 
629 
HOSTS 
This disease has been noted and collected on a large number of strains 
of barley including some 52 named varieties, in addition to a large number 
of unnamed hybrids and unclassified imported stocks. It has been 
definitely observed on the three main groups of barley: namely, the 
Hordeum distichum group (two-row barleys), the H. vulgare group (common 
six-row barleys), and H . hexastichum group (erect six-row barleys). These 
observations are summarized in Table I. 
In connection with these studies the question has been constantly kept 
in mind as to the occurrence of this or like diseases on other grains. As a 
result similar bacterial diseases have been found on wheat ( Triticum spp.), 
spelt {Triticum spelta), rye {Secede cereale ), timothy {Phleum pratense ), 
Fig. i.— Outline map showing known distribution of bacterial-blight of barley in the United States. 
and oats {Avena saliva). In each case, except that of timothy, the bac¬ 
terial parasite has been isolated and the disease reproduced by inoculation 
and the parasite recovered. 
With the exception of the bladeblight of oats the symptoms of these 
diseases are so similar as to be easily considered identical with the barley 
blight. Detailed study of the organisms, however, shows them to be 
different from that of barley. Work in connection with these is still in 
progress, and the results will be presented in subsequent publications. 
varietal susceptibility 
Observations have been made in the trial plots of the Office of Cereal 
Investigations, 1 United States Department of Agriculture, at Highmore, 
1 The writers wish in this connection to express their appreciation for courtesies extended by the various 
persons concerned at these places. 
