202 
Journal of Agricultural Research voi. xxvii, no. 4 
organisms and under unfavorable environment, it is thought that plant 
breeders may take advantage of this relationship in developing produc¬ 
tive strains and varieties of corn more resistant to root, stalk, and ear- 
rot diseases. Eliminations of homozygous strains on the basis of sus¬ 
ceptibility could be made by inoculating with one or both of the vascular 
disease organisms. The authors also feel that inoculations with Cepha- 
losporium acremonium and Aplanobacter stewarti would add considerably 
to the value of com varietal tests. 
Table XVIII.— Yield data of corn grown from good seed and susceptible seed selections , 
the experiments being conducted on brown silt loam soil at various points in Illinois, 
in 1921 
Location (Illinois). 
Previous crop. 
Total acre yield. 
Decrease in 
yield from 
susceptible 
seed selec¬ 
tion. 
Good seed 
selection. 
Susceptible 
seed selec¬ 
tion. 
Bloomington. 
Do. 
Virgin prairie sod. 
Com. 
Bu. 
88.9 
78.4 
83*3 
73-4 
81 .5 
83.2 
85-4 
69.8 
67.0 
64.4 
Bu. 
84-5 
74.6 
75-8 
71-5 
66.6 
66.7 
62.8 
5 °* 1 
59-5 
43-8 
Bu. 
4.4 
3.8 
7-5 
1.9 
14.9 
16.5 
22.6 
19.7 
7-5 
20.6 
Do. 
.do. 
Peoria. 
Clover. 
Do.. 
Com. 
Do. 
.... .do.. 
Do. 
.do. 
Virginia. 
Clover. 
Do. 
.do. 
Do. 
..... do. 
Mean. 
77-5 
65.6 
0 11.9 
a Odds 58: x. 
SUMMARY 
This paper presents the results of investigations of a hitherto unreported 
disease of com and of an organism capable of producing it. 
The most distinguishing symptom of this disease is the presence of 
blackened vascular bundles in the stalks and sometimes in the leaves. 
Associated with the disease to a notable extent are the following abnor¬ 
malities: Excessive sucker production, prolific stalks, manifestations of 
which are a tendency for ear development at many nodes or multiple-ear 
production at one node; a certain type of reddening or purpling of the 
leaves and stalks; stalks with aborted ears (barren); and stalks bearing 
nubbins only. 
The first part of this paper deals with this group of symptoms in a gen¬ 
eral way without special regard to causes. The data presented in this 
connection are based mainly on leaf and stalk color manifestations. How¬ 
ever, it was noted that the other characteristics of this group were closely 
associated. 
The data on economic importance show that high percentages of dis¬ 
eased stalks (46.6 per cent in the untreated seed and 42.7 per cent in the 
treated seed), result from planting ears selected from purple stalks and 
that yields are reduced. The yield data are presented in two ways. The 
first shows the average reduction in yield of purple-stalked plants (33.4 per 
cent with untreated seed and 20.6 per cent with treated seed). This 
