Mar. 22, 1924 
Corn Rootrot Studies 
963 
The results obtained from this work would indicate that certain of these 
fungi have a more pronounced pathological effect on the young plant than 
do others; especially when infection comes by way of the soil rather than 
through the seed. Fusarium moniliforme produced but little effect on the 
growth of the plants; even after the third week very little difference could 
be noticed between the inoculations and the controls (PI. 2, A, D, and PI. 
3 > A). . 
Gibberella saubinetii produced a distinct pathological effect on the 
seedling plants. It is quite evident from this study that this fungus must 
be one of the active factors in producing a poor stand (PI. 2, B, E, and 
PI. 3, B). Those plants which survived the seedling stage recovered 
Somewhat and continued their growth, although considerably stunted. 
In this series the principal effect of Diplodia zeae was apparently a retard¬ 
ing of the seedlings in the early stages of growth. The inoculated plants 
when not killed were much smaller than the controls (PI. 2, C, F, and PI. 
4 , A). 
The organism referred to as Cephalosporium sacchari by Manns and 
Adams (10) gave no indication whatever of injuring the plants (PI. 3, C, 
and PI. 4, B). In all of the inoculations with this organism the plants 
were equal in growth and appearance to the controls. 
The culture which Doctor Butler forwarded from Doctor Shaw of India 
as Cephalosporium sacchari Butler, was somewhat active as a corn parasite 
in the inoculations; it behaved somewhat like Gibberella saubinetii in 
destroying seedlings and retarding growth (PI. 3, D, and PI. 4, C). 
SUMMARY 
(1) Cultures of the fungous flora of soil from a field showing much 
rootrot failed to give any of the so-called rootrot organisms. Laboratory 
studies on this particular soil gave better response with com than soil 
from the adjacent field which in 1921 showed.no rootrot. These studies 
indicate that com rootrot on the field which gave poor results in 1921 was 
induced by factors other than the so-called rootrot fungi. Probably a 
combination of poor drainage and lack of fertility were the chief factors. 
(2) In these investigations it has been possible by careful selection and 
surface disinfection to obtain seed com sufficiently free internally from 
disease for experimental work. 
(3) Gibberella saubinetii proved to be the most active seedling parasite 
of com and may be an important factor in reducing stands. 
(4) In these investigations Fusarium moniliforme appeared less active 
as a seedling parasite than Gibberella saubinetii 
(5) Diplodia zeae is quite active in retarding the growth of the young 
plants. Inoculated plants were much inferior to the controls. 
(6) The organism so abundant in corn and referred to as Cephalo¬ 
sporium sacchari Butler by Manns and Adams ( 10 ) showed no patho¬ 
genicity whatever in this study. 
(7) The organism sent by Doctor Shaw from India as Cephalosporium 
sacchari Butler, which* in the writers’ hands proved to be a Fusarium, was 
somewhat active as a seedling parasite of com, when used in infection 
work. 
(8) Corn plants, provided they are properly cared for, may be grown 
almost to maturity in one-quart Mason jars. They will not reach the 
size of plants in the field, but will remain vigorous and green (PI. 4, D). 
