May 26, Z933 
Graminicolous Species of Helminthosporium 
713 
widespread attention; and in recent years Darnell-Smith (27) lists ‘‘leaf 
Stripe among the diseases affecting maize in the same Province. Yoshino 
(161) reported Helminthosporium iurcicum as occurring on Zea mays 
in the Province of Higo, Japan, in 1905. According to Butler (igi) the 
disease is fairly common in India and occurs in South Africa. The 
European literature concerning the disease does not appear to be exten¬ 
sive. Ducomet (34) > ^903, recorded its appearance under the name 
of “brulure"' in the southwestern part of France. More recently the 
publication of a paper by Zhavoronkov (162) would seem to imply its 
distribution in Russia. 
In general, leaf blight is a disease characteristic of the lat^r stages in the 
development of the host. During the season of 1920, when l^e writer 
had occasion to follow its development in the sweetcom fields of the 
western part of Long Island, it made its appearance toward the end of 
August. On plants examined on August 20, elongated straw-colored 
spots were present especially on the lower leaves, varying from 2 to 4 
mm. in width, and from 5 to 15 mm. in length. The tissues involved in 
these spots were altogether dry. Usually at this stage the dry areas 
were delimited from the surrounding healthy parts by a brownish margin, 
quite conspicuous and distinct in some instances and barely distin¬ 
guishable or absent in others. As the season progressed the affected 
areas rapidly increased in size, individual lesions frequently measuring 
more than 4 cm. in width and 10 cm. in length by September 16. (PI. 24, 
A.) By the coalescences of the enlarging spots, extensive areas embrac¬ 
ing often considerable portions of the leaf were found to be involved. 
Toward the end of September the foliage was withered to such an extent 
that some of the plants appeared, as some writers have suggested, as if 
affected by a frost. 
When leaf blight appears as late in the season as in 1920, which prob¬ 
ably was very nearly typical in regard to the development of the trouble 
at least for the nor^eastem section of the United States, the resultant 
economic damage is not likely to be serious. In most ordinary seasons 
Peck's (107) observation that Helminthosporium inconspicuum “seems 
to attack on lower leaves with vitality already impaired; not very 
noxious as it only hastens death of leaves by a few days or weeks," per¬ 
haps is not without a good deal of justification. Nevertheless, in other 
seasons, apparently as a result of weather conditions favorable to the 
fungus, the disease may- make its appearance while the plant is still 
relatively young, and thus cause very considerable destruction. Thus 
Ducomet (34) records a severe outbreak in France in 1900 during an 
exceptionally wet season. According to this writer the foliar lesions 
appear when the plants are only 0.5 to 0.6 meters high. The destructive¬ 
ness of the disease in 1903 in the States of Connecticut and Delaware 
apparently was associated also with its early appearance, Clinton (21) 
finding “many fields looking in August and September as if struck by 
early frost; heavy attack due to unfavorable season." In New South 
Wales the blight is reported (118) to appear invariably in all the late 
plantings of maize when the heavy autumn rains set in, particularly 
on low-lying situations. In the season of 1915 (u^), however— 
it appeared very much earlier owing to the phenomenally wet spring and early sum¬ 
mer. Many areas were completely destroyed on account of the leaves being killed 
off long before the plants were half grown. Where cobbing had been well advanced 
the effects were not so serious. 
