PEACH SCAB AND ITS CONTROL. 27 
each source of infection, while six, similarly treated but not inoculated served as 
controls. On June 6 this experiment was duplicated. 
Results from series inoculated on May 29. — Two fruits inoculated with the fruit strain 
of Cladosporium carpopJiilum, two inoculated with the twig strain, and one control fell 
prematurely. On Sunday, August 2, before final results were available, the remaining 
fruits of this and the succeeding series, in spite of notices and experimental labels, fell 
victims to the gastronomic proclivities of trespassers. The earlier results, however, 
were sufficient to be of material value. 
On one of the fruits inoculated with the twig strain of the fungus, eight scab lesions 
were barely visible on August 1, though no macroscopic infection could be observed 
on July 25. 
On one of the fruits inoculated with the fruit strain, very early macroscopic stages of 
infection were observed on July 25, while 16 definite lesions were evident on August 1. 
The remaining inoculated areas bore no definite macroscopic lesions on August 1, 
though their appearance strongly suggested the presence of abundant infection in 
incipient stages. 
No evidence of the disease was observed upon any controls or iminoculated fruits, 
lesions appearing only on inoculated areas. 
Results from series inoculated on June 6. — On July 25 no infection was evident. On 
August 1 scab lesions were discernible on one of the fruits inoculated with the twig 
strain of the fungus, while the appearance of the inoculated areas generally suggested 
the presence of incipient infection. The controls showed no evidence of infection. 
REISOLATION OF THE FUNGUS. 
Thorough microscopic examinations showed that Cladosporium 
carpopJiilum was uniformly associated with the lesions induced by 
inoculation. The fungus was reisolated by the poured-plate method 
and found to possess the typical morphological and cultural characters 
of C. carpopJiilum . 
CONCLUSIONS. 
These experiments show (1) that Cladosporium carpopJiilum, from 
pure cultures of single-spore strains isolated from scab lesions on 
peach twigs or fruit is capable of causing typical and abundant 
infection upon peach fruit; (2) that, in like manner, this fungus taken 
directly from twig lesions is capable of producing the disease upon 
the fruit; (3) that the period of incubation of the fungus upon the 
fruit may vary from 42 to 77 days, very early macroscopic evidences 
of the disease sometimes appearing within a slightly shorter period; 
(4) that the presence of the nutritive solution used apparently 
hindered infection; and (5) that, under the conditions of these experi- 
ments, the three superficial fungi tested are not pathogenic to peach 
fruit. 
Twig and Leaf Inoculations. 
Preliminary experiments made in 1913 showed clearly that under 
field conditions where the disease is prevalent, the chief difficulties 
attending twig and leaf as well as fruit inoculations are (1) the abun- 
dance of natural infection and (2) the difficulty of securing at will 
conditions favorable for infection. These obstacles were satisfac- 
