320 
Journal of Agricultural Research 
Vol. I, No. 4 
northern Florida, including Albany, Dewitt, Baconton, Thomasville, 
Cairo, and Bainbridge, Ga., and Tallahassee, Newport, Monticello, 
Jacksonville, St. Augustine, and Belleview, Fla.; and at San Saba, Tex. 
SYMPTOMS OP THE DISEASE 
The disease has been found to occur on both leaves and nuts of the 
pecan. On the leaves it appears in the form of irregular, reddish to 
grayish brown blotches varying greatly in size and eventually often cov¬ 
ering the whole leaf. (PI. XXXVII, fig. B.) The color of the affected 
areas is the same on both surfaces. Under conditions of moderate 
humidity, spores of the Gloeosporium type are developed singly, but 
with favorable temperature and moisture the acervuli with exuding pink 
spore masses and the black perithecia appear rather thickly scattered 
over the diseased blotches. When the greater part of the leaf blade 
becomes involved, it usually falls to the ground, and it is here, under 
natural conditions, that the acervuli and perithecia are developed. 
The blotches on the nuts are also irregular in outline, but are nearly 
or quite black and often slightly sunken below the surrounding healthy 
tissue. (PI. XXXVII, fig. F.) The perithecia and the densely gregarious 
acervuli are formed under the same conditions as on the leaves, but the 
perithecia have been found on the nuts with much less frequency. A 
serious dropping of the partially grown nuts sometimes occurs from this 
cause. 
A watery condition of the kernel is frequently found in connection 
with the anthracnose blotches. It is doubtful, however, whether it has 
anything to do with this disease, for the same condition prevails both 
with and without external signs of injury, while both cultural methods 
and microscopical study have thus far failed to locate any microorganisms 
in the watery kernels. 
MYCOEOGICAE AND PATHOEOGICAE STUDIES * 
Isolation of the Fungus 
No mature perithecia have as yet been found on fresh leaves or nuts, 
but at various times during the last three seasons ripe asci have been 
readily developed on affected leaves after an incubation of one or two 
weeks in a damp chamber. The original strains of the fungus were 
obtained in this way from nursery-tree leaves collected in the fall of 1910 
at Baconton, Ga., and were each started from a single, apparently 2-celled 
ascospore the germination of which was closely followed under the micro¬ 
scope to preclude the possibility of contamination. On several different 
culture media the colonies at once developed perithecia suggesting the 
genus Mycosphaerella, and the great majority of the slightly curved 
ascospores were apparently 2-celled, though a few showed no signs of a 
cross-septum. 
