Jan. xo, 1914 
Some Diseases of Pecans 
3i9 
Mycelium dark brown and septate, intercellular, sometimes also creeping over the 
leaf surfaces. 
Conidiophores mostly epiphyllous, short and erect, typically in dense, tawny 
clusters from stromata developed beneath the epidermis and later bursting through, 
also arising singly from the prostrate surface mycelium. 
Conidia pale olive brown, highly variable in size, 30 to loop. or more by 3 to 6 jx (see 
figs. 4 and 5), usually curved, typically subclavate, multicellular, septa less frequent 
toward the more pointed apical end. 
Habitat.—hiving leaves of Carya illinoensis , Southern States. Also possibly occur¬ 
ring on other species of Carya. Diseased nuts or leaves seen by the writer at Orange¬ 
burg, Sumter, and Charleston, S. C.; Americus, Albany, DeWitt, Hardaway, Bacon- 
ton, Thomasville, Cairo, Bainbridge, and Valdosta, Ga.; Tallahassee, Newport, Monti- 
cello, Glen St. Mary, St. Augustine, Palatka, Gainesville, Ocala, and Belleview, Fla.; 
New Orleans, ha.; and at Waring and San An¬ 
tonio, Tex. Reported also by Heald and Wolf 1 
from Victoria, Gonzales, Yoakum, and Hallets- 
ville, Tex. 
/oa 
PECAN ANTHRACNOSE 
[Caused by Glomerella cingulata (Stonem.) S. and v. S.] 
HISTORY AND DISTRIBUTION 
Pecan anthracnose, variously known 
among pecan growers as “leaf-blotch” 
and “rust,” was first noted by the writer 
during the summer and fall of 1910, at 
which time single-spore strains of the 
causal fungus were obtained from per- 
ithecia matured on the leaves in a damp 
chamber. Studies of these cultures were 
carried out during the following winter, 
and a preliminary description of the 
fungus later appeared under the name 
►of Mycosphaerella convexula . 2 
Further cultural studies of the fungus brought out changes in its 
morphology sufficient to throw it out of the genus Mycosphaerella, and 
these, together with cross-inoculation experiments upon the apple, indi¬ 
cated its close affinity to the apple bitter-rot caused by Glomerella 
cingulata . 3 No other published information concerning this disease has 
come to the notice of the writer. 
Pecan anthracnose seems to be well distributed throughout the eastern 
part of the pecan-growing territory, but it has thus far usually occurred 
only to a limited extent at any one place. Diseased leaves or nuts have 
been collected by the writer at Orangeburg, Sumter, Summerton, Charles¬ 
ton, and Aiken, S. C.; at numerous places in southern Georgia and 
3 * & e 
W/DTH OP" SFORJETS /A/ M/CftOA/S. 
Fig. 5.—Diagram showing measurements 
in width of 200 conidia. 
1 Heald, F. D., and Wolf, F. A. Loc. cit. 
2 Rand, F. V. A pecan leaf-blotch. Phytopathology, v. 1, no. 4, p. 133-138, 3 fig., 1911. 
3 Rand, F. V. Further studies on the pecan '‘rust/’ Science, n. s., v. 35, no. 913, p. 1004, 1912. 
