36 
BULLETIN 3£ 
U. S. DEPARTMENT OF AGRICULTURE. 
and placed in dry cloth-covered jelly glasses (a) in the laboratory, where the tempera- 
ture ranged from 18° to 25° C. , and (6) in the pathological garden in a covered, latticed 
compartment of the type commonly used for housing meteorological instruments. The 
cultures rapidly became air dry. The conditions precluded the further growth or 
sporulation of the fungus. Germination tests were made at intervals. The results, 
which are summarized in Table VII, show that in each series a considerable percent- 
age of spores remained viable for more than three months. Had the spores been ex- 
posed to wetting, however, it must be remembered that they would have germinated 
with the advent of favorable conditions. Thus, it is not to be expected that conidia 
ordinarily retain their viability for long periods. 
Table VII. — Summarized results of a longevity test of conidia of Cladosporium car- 
pophilum from cultures, Madison. Wis., April 16 to October 25, 1915. 
Serial No. 
Date of test. 
Place of storage of 
culture. 
Estimated germi- 
nation in 3 days 
(percent). 
Sterile 
distilled 
water. 
1 per cent 
prune 
decoction. 
786 
Apr. 16, 1915 
do 
Laboratory 
Garden 
99 
99 
50 
60 
15 
10 

99 
787 
99 
864 
June 3, 1915 
do 
Laboratory 
90 
862 
90 
996 
July 23, 1915 
do 
Laboratory 
90 
994 
90 
1004 
Oct. 25, 1915 
Laboratory 

DISSEMINATION OF CONIDIA. 
Studies planned to give insight into (1) the conditions under which 
conidia of Cladosporium carpopMlum are detached from the parent 
fungus and (2) the more important methods by which they are dis- 
seminated are briefly outlined as follows: 
EXPERIMENTAL WORK. 
Experiment 1. — Colonies of the fungus were grown in tubes on steamed bean pods 
over a bean decoction in such position that spores which might be abstricted or ab- 
jected would fall into the liquid below and germinate. The experiment was run in 
quadruplicate and continued for six weeks. The colonies developed vigorously and 
sporulated profusely, but the decoction below remained sterile. After six weeks one 
of the cultures was shaken so that the liquid came in contact with the colony. "Within 
three days the decoction was conspicuously clouded and darkened by the develop- 
ment from myriads of spores which had been detached. 
Thi3 experiment was repeated with like results, while similar tests were made with a 
variety of other media. The results were uniformly confirmatory. 
Experiment 2. — On April 19, 1915, severely infected peach twigs were placed in 
moist chambers. On April 23 a number of these twigs bearing abundantly sporu- 
lating lesions were placed (a) in moist chambers and (6) in dry chambers 1 cm. above 
glass slides smeared with glycerin. These slides were examined microscopically at 
intervals for two days. No spores were found. 
Experiment 3. — Sections of lesions were placed under the low power of the micro- 
scope in such position that tufts of spores could be observed. Currents of air were 
passed over this material by means of an aspirator. The conidiophores in certain cases 
