3 22 
Journal of Agricultural Research 
Vol. I, No. 4 
From the similarity of this fungus to the Glomerella rot of apples and 
from the omnivorous character of the latter species, as brought out in a 
paper read by Shear 1 at the 1911 meeting of the American Association 
for the Advancement of Science, it was decided to make several cross¬ 
inoculation tests on the apple. The results of inoculation tests on leaves 
and nuts and of the cross-inoculation work on the apple are given in the 
following pages. 
LEAVES 
Experiment No. i (Feb. 16, 1911).—A distilled water suspension of ascospores 
from a month-old corn-meal flask culture (strain 17, Baconton, Ga., 1910) was sprayed 
upon the lower surfaces of six potted pecan seedlings. Three of the seedlings were 
under bell jars for four days, while the remaining three were left uncovered through¬ 
out the experiment. Observations at the end of a week showed no signs of infection, 
but at four weeks numerous small discolored areas had developed on the foliage of 
the first three trees and on that of all but one of the others. The three check trees 
which had been sprayed with distilled water and left under bell jars for four days 
were sound. No further development of the disease was apparent for some time, but 
during the latter part of June large, dull reddish brown areas were noted on the leaves 
of the first three inoculated trees and on one of those which had not been covered 
with a bell jar. Specimens of these diseased leaves were at once collected, and a 
microscopical examination showed the development of an occasional Gloeosporium 
conidium. The leaves were then placed in a damp chamber, and after several days 
numerous acervuli had developed and were exuding the typical pink spore masses 
in abundance. Reisolations of the fungus were made from these acervuli. 
Experiment No. 2 (Mar. 15, 1912).—Conidia (strain 17) from 2-weeks-old com- 
meal-agar cultures were mixed with sterile distilled water and sprayed upon the 
leaves of four potted seedling trees, which were then left under bell jars for five 
days. Two check trees were sprayed w T ith sterile distilled water alone, one being 
left under a bell jar for five days and the other uncovered. After four weeks it was 
noted that discolored areas similar to those noted in inoculation experiment No. 1 
had suddenly developed, but observation at ten weeks showed no further progress of 
the disease. The last of May, however, when the leaves were getting well matured, 
the large, dead, brownish areas were fairly numerous on the leaves of three out of the 
four inoculated trees. The check trees which had been kept on the same bench but 
somewhat removed from the infected trees were entirely normal. Specimens of the 
infected leaves were placed in a damp chamber, where in a few days the Gloeosporium 
acervuli were formed. 
Experiment No. 3 (Apr. 15, 1912).—Conidial masses from a young com-meal-agar 
culture (strain 17) were smeared upon both surfaces of the moistened leaflets of two 
potted seedlings, one of which was left under a bell jar for several days. Two check 
trees were similarly treated, but not inoculated. No discoloration of the leaves fol¬ 
lowed for several weeks, but on May 20 several dead, brownish areas were noted on the 
leaves of the inoculated tree which had been under a bell jar. These leaves were 
placed in a damp chamber and in a week had formed numerous acervuli with the 
typical pink spore masses. 
Experiment No. 4 (May 1, 1912).—Two of the younger leaves from a Sovereign 
pecan were placed in a damp chamber and sprayed with a sterile distilled-water sus¬ 
pension of conidia from a 2-months-old com-meal-agar culture (strain 17). The sur¬ 
face of some of the leaflets was slightly abraded with a needle before inoculation. At 
the end of two weeks large dull-brown areas had developed on most of the leaflets, both 
1 Shear, C. L. Variation in Glomerella. (Abstract.) Science, n. s., v. 35, no. 891, p. 152, 1912. 
