Jan. 26,1924 
The Black-Bundle Disease of Corn 
183 
might not be due to species of Fusarium. Numerous isolations from the 
black bundles found in these plants consistently gave one organism, and 
pure-culture inoculations with it in the greenhouses at the University of 
Wisconsin in November, 1919, proved it to be pathogenic on corn. 
Without doubt this organism was responsible for the symptoms developed 
in the row in question. Subsequent investigations have shown, however, 
that symptoms almost identical with these may develop from other causes. 
GEOGRAPHICAL DISTRIBUTION 
The black-bundle disease of corn has been noted in Connecticut, New 
York, Ohio, Indiana, Illinois, Wisconsin, Minnesota, Iowa, South Dakota, 
Kansas, South Carolina, and California. This distribution renders it 
probable that it occurs wherever corn is grown in the United States. 
ECONOMIC IMPORTANCE 
The prevalence of this group of symptoms and their effect on produc¬ 
tiveness pf corn plants is such as to make it important that the causative 
agents be studied carefully and some effort made to lessen their occurrence. 
During 1919, 1920, and 1921, surveys of commercial fields near Bloom¬ 
ington, Ill., were made to determine the occurrence and productiveness 
of com plants having the purple-leaf-and-stalk symptom. The results are 
summarized in Table III. 
Table III .—Occurrence of purple plants in some commercial fields of Yellow Dent corn 
near Bloomington , III., grown from seed selected from plants which showed no symptoms 
of the black-bundle disease 
Year. 
Number 
of plants 
examined. 
Purple plants (main stalks.) 
Total. 
Bearing. 
Barren. 
Ears. 
Nubbins. 
Number. 
Per cent. 
Per cent. 
Per cent. 
Per cent. 
1919 . 
666 
47 
7 • 1 
34-0 
12.8 
53 * 2 
1920. 
4.857 
351 
7.2 
27.9 
31-9 
40.2 
1921. 
2,068 
112 
5*4 
28.0 
14.O 
58.0 
In addition to the preceding detailed observations, the authors have 
determined by count the percentages of purple-leaf plants occurring in a 
few scattered commercial corn fields in Indiana, Iowa, and Kansas, and 
at various places in Illinois. These have varied from a trace to 15 per 
cent. On the whole, however, it is believed that the data in the pre¬ 
ceding table are fairly representative. 
During 1920, in ear-row experimental plats of Yellow Dent corn at 
Bloomington, Ill., observations were made on 27 ear rows to determine 
the occurrence of purpling in main stalks and suckers. The relative 
number of purple-leaf plants which were barren or bore ears or nubbins 
also was noted. The seed ears were from plants that had not shown 
purpling in 1919. In planting the plats, twenty kernels were planted 
singly 14 inches apart in rows 42 inches apart. The results are given in 
Table IV. 
