Mar. 17,1923 Influence of Soil Temperature on Seedling-Blight 839 
second-leaf stage. The attacked plants first become dwarfed and chlo¬ 
rotic, then wilt (PI. 1, c), and finally fall over and become overrun by the 
parasite (PL 3, B). This latter stage is a typical wilt of the young plant. 
The old seed and the portion of the stem below ground develop the 
characteristic reddish brown color. Usually perithecia form gregari¬ 
ously on the culm near the soil line. Still other seedlings partly succumb 
to a root attack. In many cases all of the roots may be badly rotted 
and the plant considerably dwarfed. Such plants, when weather con¬ 
ditions are favorable for the development of the seedling, may send out 
new roots from the first node and entirely or partially recover (PI. 2, a, 
and 3, A). 
In many instances the reddish brown lesions occur only on the coleop- 
tile without penetrating deeper into the tissue. The symptoms under 
these conditions are very similar to the same type of lesion produced by 
light attacks of Helminthosporium; the color in the former lesion, how¬ 
ever, generally is slightly lighter. 
SEEDLING-BLIGHT OF CORN 
The relationship between seedling-blight and rootrot of com and wheat 
scab caused by Gibberella saubinetii was earlier suggested by Arthur (3) 
and later proved by Hoffer, Johnson, and Atanasoff (17). This organism 
causes heavy losses in com through the central and upper Mississippi 
Valley. In 1920, fields were reduced 10 to 25 per cent where com was 
planted on fields in which the wheat crop, heavily infected with scab, 
had been plowed under the previous fall, while field inoculation experi¬ 
ments the same year demonstrated yield reductions of 10 to 30 per cent. 
Although the distribution and prevalence of this parasite on com has 
not been definitely determined, yet it is evident that the organism is 
capable of causing heavy losses in the com crop as well as in wheat. 
lie symptoms of the seedling-blight of com caused by Gibberella 
saubinetii vary, as do those of wheat, depending upon the severity of 
attack, the age of the seedling, and soil conditions. As in the case of 
wheat, the com seedling may be attacked in various stages, the type of 
infection being similar to that in wheat (PL 4, A, B, C). The lesions are 
more definite on the com seedling, however, and usually extend from 
the kernel into the tap root and lateral roots as well as into the mesocotyl. 8 
The invaded areas are at first light brown, water-soaked regions, soon 
turning reddish brown. The kernel turns reddish brown to carmine red, 
depending upon soil moisture conditions. The type and color of the 
lesion, as well as the color of the infected kernel, are distinctly different 
from similar infections produced by Helminthosporium sp. or Diplodia 
zeae (Schw.) Lev. The badly infected seedlings become yellow and wilt 
down in a manner very similar to that described for wheat. Many of 
the plants partially recover by sending out new roots and make a fan- 
growth, although a rather high percentage of such plants fail to produce 
marketable ears. 
The symptoms of the seedling-blights of com caused by Gibberella 
saubinetii are in general very similar, the chief difference being the de¬ 
velopment of a more definite lesion on the larger stem and roots of com. 
The symptoms on both hosts are variable, depending as they do upon 
many varying factors. 
* The term -mesocotyl,” as used in this paper, follows previous usage for corn, applying to the structure 
between the attachment of thescutellum and the base of the coleoptile. 
