PEACH SCAB AND ITS CONTROL. 
35 
abundant leaf infection appears late in the season, conidia from 
leaf lesions are most plentiful in late summer and fall. In the cases 
observed by the writer, the aggregate sporulation from lesions on the 
leaf appeared to be much less than that from twig or fruit infections. 
Supporting records. — From August 21, 1913, when leaf lesions were first observed 
in Georgia, until the end of the season, they bore spores in greater or less abundance. 
In the inoculation experiments at Madison, Wis., conidia were usually present when 
the lesions became macroscopic . The amount of sporulation and its period of duration 
upon the individual lesion appear to vary greatly with conditions. 
VIABILITY AND LONGEVITY OF CONIDIA. 
Hundreds of germination tests conducted during the seasons of 
1912, 1913, and 1914 showed that freshly produced, normal conidia 
from fruit, twig, or leaf lesions are capable of germinating in sterile 
distilled water, rain water, or a large variety of nutrient solutions. 
The frequent paucity of germination from miscellaneously collected 
field material indicated, further, that under unfavorable conditions 
the viability of spores may diminish rather rapidly with age. This, 
however, seems to be of relatively little practical significance, since 
fresh conidia may be produced with the advent of conditions favor- 
able for infection. The summarized results of a few typical germina- 
tion tests are given in Table VI. 
Table VI. — Summarized results of typical germination experiments with conidia of 
Cladosporium carpophilum from field .material at Cornelia, Ga., in 1913 and at 
Madison, Wis., in 1914. l 
Serial No. 
Date. 
Variety. 
Source of lesion. 
Estimated germi- 
nation in 3 days 
(per cent). 
Sterile 
distilled 
water. 
1 per cent 
prune de- 
coction. 
438 
July 1, 1913 
July 22,1913 
Julv 24,1913 
July 26,1913 
Aug. 22. 1913 
Apr. 13; 1913 
June 7, 1913 
June 21,1913 
July 7, 1913 
July 27,1913 
Oct. 7, 1913 
Oct. 9,1913 
Nov. 1, 1914 
Oct. 7,1913 
Oct. 9,1913 
Oct. 23,1913 
Oct. 9, 1913 
Belle 
Fruit 
50 
10 
30 
20 

80 
95 
50 
10 
30 
50 
40 
95 
60 
40 
60 
95 
90 
492 
Elberta 
do 
15 
505 
do... 
do. 
Fox 
Elberta 
Belle 
do 
do. 2 
do 
Overwintered twig 
.. ..do. 2 
507 
90 
536 

275 
99 
374 
99 
420 
Elberta 
do. 2 
70 
474 
do 
do 
Summerour... 
do 
Chili 
do. 2 
do. 2 
Current year's twig 
.do 
do 
10 
494 
30 
558 
95 
566 
95 
731 
" 99 
660 
Summerour... 
do 
Leaf lamina 2 
Petiole 2 
95 
668 
95 
670 
do 
do 
do 
Leaf lamina 
60 
725 
99 
* These germination tests were made in open drops upon clean sterile glass slides in moist chambers and 
incubated in difiuse light in the laboratory. "Unless otherwise stated the spores were secured from fresh 
field material. 
2 Spores secured from material which had been held in moist chamber 2 to 4 days. 
A longevity experiment is briefly reported below. 
Experiment 1. — On April 16, 1915, abundantly sporulating 17-day-old cultures of a 
t%ig strain of the fungus on steamed bean pods were removed from the culture tubes 
