Mar. *2, 1924 
Corn Rootrot Studies 
961 
gm. of calcium oxid in 15,000 gm. of soil; this is equivalent to 1,000 
pounds of lime for a 2,000,000-pound acre (about a 6-inch acre); pot iB 
received the equivalent of a treatment of 400 pounds of 2-8-6 fer¬ 
tilizer per acre, that is, 1 gm. sodium nitrate, 3 gm. 14 per cent acid 
phosphate and 1 gm. potassium chlorid in 15,000 gm. of soil; pot 2A 
received the equivalent of 500 pounds of lime per acre, that is, 3.75 gm. 
calcium oxid in 15,000 gm. of soil, and pot 2B received a treatment 
similar to pot iB. 
Com which was apparently free from infection and which had been 
surface-sterilized according to the method previously given (p. 959), was 
planted, 15 kernels in each pot. The pots were planted on December 22, 
1921; and on January 14, 1922, all plants except four in each pot were 
taken out. Several of the plants removed showed external evidences of 
infection and crushed cultures were made of the hypocotyl and lower 
part of the stem of each plant. No differences in the fungus floral content 
in any of the pots could be noticed. The plates showed large numbers of 
Bacillus radicola, several colonies of a Fusarium sp., a few colonies of 
F. moniliforme and one colony of Cephalosporium sacchari. On February 8, 
two plants were removed from each pot, examined and photographed. 
The examination showed that in pot iA the hypocotyls were healthy. 
In pot iB the hypocotyl of one plant was healthy and the other showed 
a pronounced lesion. In pot 2 A the hypocotyl of one plant was dead and 
the other showed pronounced lesions. In pot 2B the hypocotyls were 
healthy. The work was discontinued here. The results obtained in the 
laboratory and greenhouse were exactly the reverse of the conditions 
found in the field, a fact which would seem to indicate that the “sick” 
condition of Field No. 1 was not due to the presence of pathogenic organ¬ 
isms in the soil. Just what the sick condition was caused by is still an 
open question. It might be the result of poor drainage or of some other 
purely physical condition. 
INFECTION EXPERIMENTS WITH CORN ORGANISMS 
♦ 
The major part of these studies was concerned with trying to deter¬ 
mine the effect of four different fungi upon corn, namely, Fusarium 
moniliforme t Sheldon; Gibberella saubinetii (Mont.) Sacc.; Diplodia 
zeae (Schw.) L6v.; and the fungus tentatively referred to by Manns 
and Adams (jo) as Cephalosporium sacchari Butler. As has been pre¬ 
viously stated, these are the fungi most commonly associated with com 
ear, stalk, and root rots. 
In order to reduce the probability of error the work was triplicated. 
The jars were handled according to the method previously described. 
The first series contained ten jars. Jars No. 1 and No. 2 were inoculated 
with Diplodia zeae; 3 and 4 with Cephalosporium sacchari: 5 and 6 with 
the organism tentatively referred to as Cephalosporium sacchari and with 
Fusarium moniliforme; 7 and 8 with all four of the fungi under consid¬ 
eration, and 9 and 10 were held as controls; that is, were not inoculated. 
These jars were planted on February 28 and were examined on March 17. 
The results on the latter date were as follows: 
Jar No. 1.—Inoculated with Diplodia zeae . One plant dead and 
another almost dead. Some Trichoderma koningii found. Both plants 
contained large quantities of Fusarium moniliforme spores in the stems. 
Jar No. 2.—Same as Jar 1 except that no F. moniliforme spores were 
found on the stems. Some, however, appeared on the roots. 
