342 
Journal of Agricultural Research 
Vol. I, No. 4 
Quercus gambelii proved to be the most susceptible when inoculated, 
and Q . lobata the second; Q . alba and Q. rubra were slower in showing 
the effects of the fungus; while Q. virginiana and Q . texana were not 
affected. 
In a number of cases the plant was in a dormant condition when 
inoculated and seemed not to be affected by the fungus, but at the 
leafing-out season no leaves were formed from the point of inoculation 
outward to the end of the branch (PI. XXXVIII), while the other part 
of the plant put out leaves and grew in a normal manner. After inocu¬ 
lation the twig darkened slightly, but no further external development 
took place. No pycnidia were formed as usual, even after the growing 
season commenced. 
The failure of part of the inoculations was probably due to the time 
of inoculation, as it was found that the twigs are the most susceptible 
when the new shoots are just coming out. Practically all the inocula¬ 
tions made at this time were effective, but after two weeks from the 
time of leafing-out the susceptibility lessened greatly, only a small 
percentage made from that time on having any effect. 
In some cases after the dying of the tip the branch put out new shoots 
below and apparently overcame the injurious effect of the fungus. 
Inoculations from cultures of the mature stage developed somewhat 
slower than those from the Macrophoma stage. 
The inoculations of Quercus prinus in the field were more conclusive. 
Fifty inoculations were made on May 8, 1912, and 28 of these were 
effective. Twenty-six were made in the usual manner by a slight inci¬ 
sion in the bark and the inserting of a portion of the mycelium into 
the wound. Fifteen were made by inoculating with spores. Of the 
latter, 10 were made by placing the spores in the incision and 5 by 
puncturing the bark with a needle and spraying the injured part with 
spores suspended in corn-meal infusion. Four inoculations were made 
by binding the mycelium on the surface of the uninjured twigs. Five 
leaves were pricked slightly with a needle and sprayed with the spores— 
one on both upper and lower surface, two on the upper surface only, 
and three on the lower only. Checks of both leaves and twigs were 
treated in the same manner. The leaves all healed normally and were 
not affected by the fungus. Three of the twigs that were sprayed with 
spores withered and died, while the two others healed normally. Four 
of the twigs inoculated with spores by a slit in the bark withered from 
the point of infection out to the tip; the others were uninjured by the 
fungus and put out new leaves and shoots. Of the 26 twigs inoculated 
with mycelium on wounds, 21 showed the effects of the fungus, most of 
them dying completely from point of inoculation outward; those 
unwounded showed no effects whatever but grew in a normal manner. 
The inoculations were made partly on small saplings and partly on the 
small branches of larger trees. The largest sapling which died com- 
