652 
Journal of Agricultural Research 
Vol. XXIV. No. 8 
barley is grown to any extent, the damage varying from a relatively small 
amount to approximately one-fifth of the crop. From Canada the 
disease has been reported by Giissow {48) and by Fraser (45). Hauman- 
Merck {^2) noted the prevalence of Helminthosporium gramineum on 
barley in Argentina to an extent unknown in Central Europe. Yoshino 
{161) and Ideta (65) have recorded the disease in Japan, where Hori 
(63), in 1918, observed an unusually severe outbreak. Chou {20) notes 
Pleospora graminea Died, on barley among the pathogenic fungi prevalent 
in the locality of Nanking in China. In India, the stripe disease has been 
studied by Butler (19), who states that the damage caused in that country 
is less than that recorded in European literature. 
The symptoms of the stripe disease were described correctly by von 
Post (jjj), Pammel (102), and Rostrup {124), and in an especially 
detailed manner by Ravn (rry). The &st evidence of infection may 
often be recognized in the unfolded leaves of young seedlings by the 
presence of small pale spots, although generally at this stage the mani¬ 
festations of abnormality are not pronounced. Eater, usually about 6 
weeks after sowing, after a number of leaves have become fully developed, 
these organs begin to show longitudinal, etiolated, yellowish stripes, 
often extending from the base of the blade to the tip. A single broad 
blade may show from 5 to 7 of these stripes although a smaller number 
is much more common. Not infrequently the stripes are interrupted 
and are thus replaced by numbers of elongated yellowish streaks. In 
any case, the similarity to ribbon grass then constituting one of the most 
sti^ing characteristics of the disease, is soon modified by the appearance 
of dark brown discoloration in longitudinal elongated streaks. These 
brown discolored streaks are most apt to occur especially at the margins 
of the yellowish stripes, the tissues of which have now become dry and 
brittle, but often extend also as brown lines beyond the base of the blade, 
into the upper portions of the sheath. Often the brown streaks are 
separated from the remaining healthy parts by a yellowish zone within 
which the chlorophyll has largely disappeared. At this intermediate 
stage, especially when the brown streaks are short and relatively wide, 
the disease is apt to be mistaken for netblotch or spotblotch. Later 
the likelihood of a wrong identification is again diminished, for finally 
the remaining green tissues are also involved, the yellow and brown dis¬ 
colorations gradually fade into a uniform dark gray or brownish gray, 
the dead, rather brittle tissues split freely, and a dark efflorescence con¬ 
sisting of the abundant fructification of the parasite makes its appear¬ 
ance on the longitudinal foliar strips. (PI. i, A.) As the mechanical 
rigidity of the diseased leaf tissue becomes greatly lessened during the 
later stages, the leaf blades or their shredded remain.*! (PI. i, Ah-e) usually 
droop or hang down in a characteristic way. 
The effect of the parasite on the stem is equally pronounced. The 
elongation of this organ incident to heading, especially of the uppermost 
internodes, is considerably reduced or sometimes almost entirely sup¬ 
pressed. As a result the height of the plants is correspondingly reduced, 
diseased specimens generally not attaining much more than half the 
height of healthy individuals. Most frequentljy the spike never becomes 
visible, but remains entirely enclosed in the basal portion of the upper 
leaf sheath. In other instances, the inflorescence is thrust into the upper 
part of the upper leaf sheath, and, failing to emerge normally, protrudes 
partly from the opening on the side of the latter. (PI. i, A.) This abnor¬ 
mal mode of emergence generally involves some distortion of the awns, as 
