19, 6 Welles: Leaf Spot of Averrhoa Carambola 749 
The conidiophores are produced in clumps which arise in sto- 
matal openings. They are light brown, simple, erect, and are 
3- to 7-septate. The average conidiophore measures 52.51 » long 
and 5.04 » wide, the extremes being 61.64 to 47.84 » long and 5.52 
to 4.41 » wide. $ 
The conidia are hyaline, short, straight or slightly curved, 
erect, larger at the basal end, and taper slightly to a blunt 
point. The average conidium measures 45.26 » long and 
4.23 » wide, the extremes being 67.52 to 27.96 » long and 5.2 
to 2.8 » wide. They are 4- to 7-septate. 
CULTURAL CHARACTERISTICS 
Isolation is easily accomplished by plating the diseased tissue 
directly on corn meal medium. ‘The mycelium develops with 
moderate rapidity. 
At first the mycelium appears in a very thin growth. Later 
it develops into a rather thick mass of closely packed hyphae. 
With age the central portion of the mycelial growth turns gray- 
ish green and is surrounded with a thin band of white mycelium. 
The cultures have been kept for but a short period, so no fruit- 
ing bodies have developed. 
CERCOSPORA AVERRHOI sp. nov. 
Conidiophores light brown, simple, erect, 52.51 by 5.04 p, the 
extremes being 61.64 to 47.84 by 5.52 to 4.41 »; tufted, arising 
from stomatal openings, on both surfaces of the leaf but more 
commonly on the lower surface. Conidia hyaline, short, straight 
or slightly covered, erect, 4- to 7-septate, average measures 
45.26 by 4.23 », the extremes being 67.52 to . 27 96 by 5.2 
to 2.8 p. Readily cultured on starchy media, producing first 
thin, white hyphae, with age becoming thickly matted and 
grayish green; spores not commonly produced in culture. 
On leaves of Averrhoa carambola Linn., causing amphigenous, 
circular or irregular, grayish brown spots with yellow borders, 
3 to 5 millimeters in width; at Los Bafios, Laguna Province, 
Philippine Islands. 
CONTROL 
Control experiments with Bordeaux mixture were commenced 
the ; The 
ly 18, 1921, about the beginning of the rainy season. 
ental mixture was made up according to the following for- 
mula: 1.8 kilograms copper sulphate, 2 kilograms stone lime, 
190 liters of water. , 
