336 
Journal of Agricultural Research 
Vol. I, No. 4 
SUMMARY 
The nursery-blight is a serious disease of young trees, but is rarely 
found to be injurious in orchards. Its distribution corresponds closely 
with that of the host. The casual fungus, Phyllosiicia caryae Peck, 
attacks only the leaves of the pecan. Infection first becomes evident 
through the formation of tiny circular, dark-brown spots, which increase 
gradually in size and finally become grayish white in the center of the 
upper surface and usually blackish throughout on the lower. Entire 
defoliation of young trees sometimes takes place. Spraying with Bor¬ 
deaux mixture has proved a very effective method of control. Since the 
disease is primarily a nursery trouble, the question of disease resistance 
would not be applicable in this connection. All attempts at pure-culture 
inoculation have been successful. A combination of high humidity and 
temperature seem best to favor the spread of the disease. The fungous 
mycelium ramifies through the intercellular spaces above the lower 
epidermis and throughout the mesophyll tissue. Pycnidia are few on 
the living leaves, but are produced in abundance on some culture media. 
The brown leaf-spot usually causes very little injury, but is widely 
distributed and occasionally during wet seasons some defoliation may 
result. The fungus Cercospora fusca, emend, sp., causes dark reddish 
brown spots of uniform color on both leaf surfaces. These are at first 
somewhat angular in outline as bounded by the veins of the leaf, but 
may later become roundish and more indefinite in their margins. There 
appears to be little difference in resistance to this disease among the 
varieties now commonly planted. The rather limited observations upon 
the effect of Bordeaux mixture were favorable to the control of the 
disease. Pure-culture inoculations were highly successful, giving the 
typical disease symptoms. The temperature relations were very sim¬ 
ilar to those of the nursery-blight. The mycelium is largely inter¬ 
cellular in its growth, but aggregations of fungous cells break through 
the upper epidermis to bear the pale tawny conidial clusters, and a 
creeping surface mycelium sometimes occurs. True spore formation 
has not taken place in culture. 
The pecan anthracnose is well distributed, but hitherto has not 
usually been very serious at any one point. It has been shown by cul¬ 
tural and cross-inoculation work to be due to Glomerella cingudata 
(Stonem.) S. and v. S., the fungus causing bitter-rot in apples. On the 
leaves infection causes the formation of irregular reddish to grayish 
brown blotches varying greatly in size and eventually often covering the 
whole leaf. On the huts the blotches are also irregular in outline, but 
nearly or quite black and often slightly sunken below the surrounding 
healthy tissue. The production of acervuli and perithecia occurs under 
suitable conditions of temperature and humidity. The problem of control 
is largely in the tentative stage, though from the work of Scott and others 
