Journal of Agricultural Research 
Vol. XXVII, No. 4 
I98 
also was the case in 1922 both in inoculated plants from horny, nearly 
disease-free seed (PI. 5 A, B, C) and in ear rows from naturally infected 
seed (PI. 4 A, B). However, inoculations of various strains of corn with 
this organism do not produce this symptom consistently. Starchy com¬ 
posites, especially, show less tendency to sucker when inoculated with this 
organism, but the main stalks are more markedly affected, resulting in 
numerous weak, spindly, low-yielding plants (PI. 5 C, D). In this latter 
case the reduction in yield generally is greater than in better strains of 
corn which show increase of suckering. 
Table XIV gives the results of inoculations with Cephalosporium acre- 
monium with all conditions similar to those described in Table XII, ex¬ 
cept that the date of planting, May 28, was later, that the control plants 
were not injected with sterile water, and that five rows in a third series 
were inoculated with Aplanobacter stewarti (E F S) McCul. This bac¬ 
terial organism, also pathogenic on dent com, is further similar to C. 
acremonium in its attack on corn in that it causes vascular infections of 
the plants. Yields of the plats, the plants of which were injected with 
sterile water, were compared with the yield from a number of corresponding 
control plats not thus injected. The injections of water seemed to have 
no effect. In every case the yields from the group of plants receiving 
sterile water injections equaled or slightly exceeded the corresponding 
ones not thus injected. Therefore, mechanical injury caused by the 
inoculations was considered negligible. 
In agreement with the results given in Tables XII and XIII, the results 
given in Tables XIV and XV show an increase of suckers, purple stalks, 
prolific stalks, nubbin ears, and barren stalks, and a significant decrease 
in good ears and yield from the plants inoculated with Cephalosporium 
acremonium. 
Comparing the inoculations of the two parasites, Cephalosporium 
acremonium increased the number of purple stalks (152.4 per cent) while 
Aplanobacter stewarti did not increase them, and although Aplanobacter 
stewarti increased suckering, the C. acremonium plats averaged 110.8 
per cent more suckers than the A. stewarti plat. In a similar way there 
were 55.3 per cent more nubbin ears in the C. acremonium plats than in 
the A. stewarti plats. The number of barren stalks was increased and 
the yields decreased about the same amount in both inoculations. 
Therefore, the outstanding differences in the effects of those two patho- 
genes causing vascular diseases of com are the increase in the number 
of purple stalks and the larger number of suckers, prolific stalks, and 
nubbin ears caused by C. acremonium. 
In Tables XII to XV it will be noted that the reductions in yield due 
to the hypodermic inoculations with Cephalosporium acremonium and 
Aplanobacter stewarti range from slight increases to as much as 44.6 per 
cent reduction in acre yields of marketable corn. Table XVI presents 
data comparing the resistance and susceptibility of different seed selec¬ 
tions from various strains of Yellow Dent corn to the vascular diseases 
induced by C. acremonium and A . stewarti . Data from inoculations with 
Gibberella saubinetii on com grown from similar seed from the same 
sources are included to show that, in general, seed lots susceptible to 
these two vascular diseases are likewise susceptible to one of the rootrot 
organisms. 
