704 
Journal of Agricultural Research 
Vol. XXIV, No. 8 
CONTROI< 
As the disease of barley and wheat due to Helminthosporium sativum is 
attributable on the one hand to primary infection of the seedling, resulting 
from the use of infected seed, and on the other to secondary infection of 
the growing plant, two lines of procedure in attempting their control are 
indicated. To prevent primary seedling infection, the use of none but 
clean seed naturally suggests itself. If affected seed stock must be used, 
the hot air treatment devised by Atanasoff and Johnson (J) constitutes a 
very effective means of obviating the primary manifestations of the dis¬ 
ease in barley. Although these authors did not include wheat seed in¬ 
fected with H, sativum in their tests, there is good reason to believe that 
the hot air treatment will prevent the appearance of primary lesions in 
the resulting seedlings. Some preliminary trials with badly discolored 
wheat seed carried out in Washington indicate that treatment with cer¬ 
tain organic mercury compounds controls seedling blight quite com¬ 
pletely. 
Although the elimination of primary infection, by bringing about a re¬ 
duction of the amount of inoculum available early in the season, may well 
be expected to moderate subsequent infection, it is scarcely probable that 
injury to individual fields of barley, wheat, and rye can be prevented 
except by controlling the fungus on a more comprehensive scale. Such 
control, barring the likelihood of strictly specialized races, would appear 
to involve measures like the widespread use of clean or disinfected seed by 
all growers within the community, and the suppression of uncultivated 
grasses that serve as congenial hosts, as, for example, quack grass. Gen¬ 
erally approved agricultural practices, like judicious rotation of crops, 
clean cultivation, and the use of manure containing diseased straw only 
on fields that are to be planted to immune crops—all tending toward 
making the inoculum of one season ineffective in reestablishing the fungus 
in the next—also ought to prove beneficial. 
As methods of disease control contemplating the approximate elimina¬ 
tion of a fungus as generally distributed as Helminthosporium sativum 
are necessarily rather uncertain, the possible development of resistant 
varieties of the various cereals affected would seem to hold forth most 
promise. The work of Hayes and Stakman (55) revealed pronounced 
differences in susceptibility to spotblotch between various varieties of 
barley, and showed that resistance is inherited. Thus, on crossing a rough- 
awned resistant type ^vith a smooth-awned susceptible one, these authors 
demonstrated the possibility of obtaining a variety combining the desir¬ 
able smooth-awned character of one parent with the resistance of the other. 
A study of commercial varieties suggested that resistant barleys of any 
botanical group could be produced. While in wheat and rye the organs 
most severely attacked are the roots and stem rather than the leaves, it is 
hardly possible that this fact in itself would constitute an obstacle to suc¬ 
cessful breeding work with these cereals. 
HELMINTHOSPORIUM MONOCERAS, N. SP. 
In September, 1920, the writer observed near Port Washington, N. Y., 
on Lotig Island, a stand of barnyard grass (Echinochloa crus-galli [L.] 
Beauv.) that appeared to be quite severely affected by a type of spotblotch. 
(PI. 20, A.) The upper leaf blades, otherwise entirely green and healthy, 
bore dark brown or chocolate-colored spots (pi. 20, B), measuring 0.3 
