4 BULLETIN 534, U. S. DEPARTMENT OF AGRICULTURE. 
In 1907 Scott and Quaintance (5) described the disease and gave 
tentative recommendations for its control. 
The first extensive report on the life history of the fungus and the 
first definite recommendations for its control were published by Scott 
and Rorer (6) in 1907. Later (1909), by comparison with type speci- 
mens they identified the fungus definitely as Phyllosticta solitaria E. 
and E. and determined by cross inoculations that the fungus found on 
leaves, fruit, and twigs is identical. They further determined that 
the fungus passes from one season to another in small cankers on the 
twigs. 
Sheldon (7) in 1907 reported the presence of the fungus on twigs. 
He was the first to identify the fungus as Phyllosticta solitaria E. 
and KE. and gave a good. description of the disease on leaves, fruit, 
and twigs. 
Lewis (3) gave a detailed description of the disease on the fruits 
of different varieties and noted particularly the destruction of fruit 
spurs. | 
THE FUNGUS. 
The life history of the causal organism has been traced by Scott 
and Rorer and by Sheldon. They found that the fungus passes the 
winter alive in the small twig cankers, where it grows and develops 
spores the following spring. From this source the young fruit, 
leaves, and twigs become infected early in the season. Later, spores 
from the spots of apples thus affected may spread the disease farther 
during the current season. | 
Scott and Rorer found almost no spores in mummied fruits of the 
preceding year and concluded that mummies were not a source of the 
spring infections. At different times during the spring of 1915 the 
writer undertook to examine for spores something more than a bushel 
of mummied fruits that had been badly affected with blotch during 
the preceding year. The varieties selected were Ben Davis and Mis- 
sourl (/issourt Pippin), both of which are very susceptible to the 
disease. On the average, six blotched areas on each apple, especially 
selected for the large number of pycnidia contained in them, were 
examined. The period during which the mummied fruits were col- 
lected and examined extended from April 1 to June i, 1915. The 
fruits were from trees particularly noted during the preceding year 
as heavily infected with the disease. It was thought that by examin- 
ing such specimens at intervals during this period it could be ascer- 
tained (1) whether spores remained in the pycindia through the 
winter, (2) whether an ascogenous form was produced during the 
winter or spring, and (3) whether new pycnidia with spores were 
produced after the growing season started in the spring. All the 
material was sectioned on the freezing microtome and examined care- 
