194 
Journal of Agricultural Research 
Vol. XXVII, No. 4 
Indicator media containing dextrose, saccharose, and glycerine, respec¬ 
tively, with cresol purple to detect increase in acidity and cresol red to 
detect increase in alkalinity were used in an attempt further to classify 
the various isolations of Cephalosporium acremonium . No data were 
obtained that would separate the sweet com from the dent corn isolations. 
Although each isolation behaved consistently in a number of trials, it 
was found that two isolations from the same stalk might differ in their 
behavior on these media. Work is being continued on the organism, 
but for the present the various isolations, differing in minor character¬ 
istics, are regarded as various strains of C. acremonium. The organism 
supplied by Manns and Adams is also considered as representing this 
species rather than C. sacchari. 
LIFE CYCLE OF CEPHALOSPORIUM ACREMONIUM 
Infected ears carry the organism internally in the seed. As will be 
shown later, Cephalosporium acremonium is definitely pathogenic. It 
develops with the germinating kernel and causes a systemic infection of 
the plant through the vascular system (PI. 6, A). By this means, it 
invades the ears and eventually the kernels. In this manner it is carried 
over to the following season. Occasionally an ear can be found which is 
externally overrun. In observations extending over a period of three 
years, only one such ear has been found. Probably an especially damp 
harvest season or poor storage conditions are necessary for this develop¬ 
ment. It seems possible that with such development, the infection 
might spread from ear to ear. Extensive inoculation experiments in 
which spore suspensions were placed on the seed gave, on the whole, 
negative results (see Table XI). However, the question of soil infection 
has not been determined definitely as yet. 
Seed infection can be determined microscopically on limestone-sawdust 
germinators as described by Holbert and Hoffer (21, p. 14-16), but the 
symptoms are easily overlooked so that up to the present only a fair 
degree of accuracy has been attained by this method. 
Infected germinating kernels have blanched, white tips, sometimes 
with noticeable mycelial growth. Often, however, the mycelial growth 
can not be seen until examined microscopically. When the symptoms on 
the germinator are overlooked the ears often are chosen for seed, because 
germination and the vigor of the infected seedlings are seldom impaired 
at this time. 
In experiments, macroscopic examination of germinating kernels is 
followed by microscopic examination of those suspected. In this way the 
infected ears can be accurately determined (PI. 6, E). In two instances 
30 ears of this type were obtained. Two composites made from an equal 
number of kernels from each of these ears showed 65 per cent and 95 per 
cent Cephalosporium infections, respectively. 
Cephalosporium acremonium has been isolated from black bundles in 
first leaves (PI. 6, F), from bundles in the stalks (PI. 1 (right), 3 B), 
from the shanks, from the cobs, and from the kernels. 
INOCULATION EXPERIMENTS WITH CEPHALOSPORIUM ACREMONIUM 
These experiments were conducted near Bloomington, Ill., on uniform, 
well-drained, fertile brown silt loam soil. The land on which the inocu¬ 
lation experiments were located never had been cropped previously. 
