3°8 
Journal of Agricultural Research 
VoJ. I, No. 4 
surface of the infected areas was almost black. Infection had taken place upon all 
the leaves inoculated, while none of the check trees showed any signs of the disease. 
Experiment No. 3 (Dec. 7, 1912).—The mature leaves of four seedlings were inocu¬ 
lated from 3-weeks-old, sporiferous corn-meal-agar cultures (Florida strain 122), and 
those of three other seedlings from nonsporiferous synthetic-agar cultures of the same 
age and strain. The seven inoculated plants and four checks were kept under bell 
jars for three days. Observations at two weeks showed the leaves of the first set with 
tiny dark-brown specks scattered over the inoculated areas and with some of the 
spots beginning to show the grayish centers. The leaves inoculated from the syn¬ 
thetic-agar cultures were similar, but not quite so far advanced. The check trees 
all remained uninjured. 
Experiment No. 4 (Dec. 7, 1912).—The mature leaves of three seedlings were in 
like manner inoculated from 3-weeks-old, sporiferous corn-meal-agar cultures (Texas 
strain 127). At the end of one week the spots were just becoming visible, and after 
two weeks the centers were turning gray on the upper surface, while the borders 
remained the typical dark brown. There were no evidences of the disease on the 
two check trees. All five trees had been covered with bell jars for the first three 
days. 
Experiment No. 5 (Dec. 18, 1912).—Two trees were inoculated from com-meal- 
agar cultures isolated from one of the trees of experiment No. 3 (strain 163). Typical 
infections appeared at five to seven days, and these gradually increased in size for 
three weeks, finally taking on the grayish center and dark reddish brown border 
above, with the color almost black below. The check trees remained healthy. 
Experiment No. 6 (Dec. 18, 1912).—The mature leaves of three seedlings were 
inoculated from sporiferous com-meal-agar cultures of two weeks’incubation (Florida 
strain 122). In this case the pycnidia were broken up in sterile distilled water and 
sprayed upon the leaves. The three check trees were sprayed with sterile distilled 
water, and all six trees were left under bell jars for three days. On removing the bell 
jars it was noted that tiny dark-colored specks were forming over much of the areas 
inoculated. These later proved to be the typical spots of the nursery-blight. No 
evidence of disease appeared on the check trees. 
Experiment No. 7 (Dec. 23, 1912).—The sporiferous pycnidia from young com 
meal-agar cultures (Florida strain 122) were broken up in sterile distilled water and 
sprayed upon the upper and lower surfaces of the leaves of three seedling pecan trees, 
the leaves having previously been washed. Three days after inoculation sample 
inoculated and check leaves were collected. These were killed and bleached in 
alcohol, stained with eosin, and examined superficially under the microscope. The 
conidia themselves, being almost bacillar in size, could not be seen with the low 
power necessary in any such examination. However, here and there could be dis¬ 
tinguished a very fine mycelial growth stained pale pink by the eosin, and in a number 
of cases hyplise were clearly seen entering the leaf through stomatal pores or openings 
left by the breaking off of leaf hairs and resin glands. In one case the branching 
hypha could be followed some distance beneath the epidermis from the stoma through 
which it had entered. The check leaves showed no such fungous growth entering the 
leaf. 
After a week an examination of the leaves left on the trees showed tiny dark-colored 
spots scattered over the inoculated areas, while at two weeks the typical grayish 
centers had developed. The check leaves were still without injury. 
In the above detailed experiments the leaves of 24 pecan seedlings 
were inoculated at different stages of maturity and with three strains of 
the fungus. Every inoculation was successful, and in no case did any of 
the check trees show signs of the disease. These data seem to establish 
the parasitism of the fungus beyond any doubt. 
