502 
Journal of Agricultural Research voi. xxm, no. 7 
3.5 to 8 n by 1.8 to 2.6 /x. On culture media their range is somewhat 
longer, as 4.3 to 10 \x by 1.7 to 3 \ it. The conidiophores range from 16 
to 40 n in length. The conidia at time of germination are much larger 
and often septate, as shown in Plate 1, B. 
GIBBERELEA SAUBINETII 5 (MONT.) SACC 
This parasite has been observed extensively on cereals in this country 
as well as abroad. Johnson, Dickson, and Johann ( 22 ) have shown this 
to be the most prevalent organism in producing wheat scab. In their 
study of over 1,000 specimens collected in 15 states, Gibberella saubinetii 
proved to be the chief causal organism. Hoffer and Holbert (20) men¬ 
tion its importance in connection with the root and stalk rot of corn. 
The description of Fusarium 2 by Burrill and Barrett (6) strongly indi¬ 
cates they were working with this species. 
As with the preceding species, no uniform symptom is constantly 
associated with the infection of seed com by this parasite. Plate 13, 
A, B, illustrates the extreme type of infection. We have consistently 
observed such infection confined to the tip of the ear. Such ears show 
a superficial growth of the mycelium between the rows of kernels which 
are found to be rotted throughout. In some instances the silk is matted 
with the mycelium. It is possible that such an association indicates 
that infection was established before maturity. The ear illustrated in 
Plate 13, A, was exposed to the changeable weather conditions long 
after the usual harvest time. Kernels from the tip of this ear were 
disinfected and crushed in a melted tube of agar for a poured plate. 
A pure growth of Gibberella saubinetii was recovered. Kernels from 
the butt of this ear treated in a similar manner showed no fungous 
growth. 
The symptoms and effect in the kernels are very similar to that of 
wheat scab infection. White varieties of com often show a pink dis¬ 
coloration of the kernels, but it is not so conspicuous on yellow varieties. 
On shelling the kernels from the infected end, a pinkish discoloration 
of the fruit cups is often revealed. This appearance is only evident 
where heavy infection occurs. The rotted kernels are very brittle. The 
starch in the endosperm is loose or readily crumbles. The embryo in 
such seeds is completely destroyed. All parts of the kernels under 
such conditions are invaded by the mycelium. The mycelium is intra¬ 
cellular and intercellular with the same resultant effect on the fruit as 
reported by Adams (r, 2) for wheat scab infection. 
Infection of seed com is also found which to all external appearance 
is healthy. On the germinator such com will show the effused growth 
of the fungus at the cap in about five days. Germination is retarded 
and in many instances inhibited on the germinator by the presence of 
this parasite. The perfect stage has developed on infected kernels that 
have been allowed to dry out on the germinator under conditions of room 
temperature. We have not observed the perithecia to develop in any 
of our cultures. Perithecia are commonly found fruiting at the nodes 
of old cornstalks in the field. The perfect stage has been found fruit¬ 
ing abundantly on kernels as well as at the butt and in the fruit cups 
on ears overwintering in the field. 
* See footnote 4, p. 500. 
