6 BULLETIN 534, U. S. DEPARTMENT OF AGRICULTURE. 
are concerned, while many are still produced from the diseased 
fruits. 
It is a rather curious thing that leaf infections are comparatively 
rare in Arkansas, whereas in Kansas they are rather abundant. This 
may be partly, though not wholly, accounted for by the more 
numerous cankers and consequent heavier infection in Kansas 
orchards. 
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Fic. 1.—Section through a pycnidium of Phyllosticta solitaria produced in 1914 
on a blotched spot of a young Ben Davis apple. 
The fruiting bodies (pycnidia) are found on the newer parts of the 
twig cankers until the cankers are about 4 years old. They are most 
plentiful on young cankers which had begun their development dur- 
ing the previous season. They occur on the leaves also, particularly 
in the lesions on the midrib and 
petiole, and in the blotches on the 
fruits. The pycnidia (fig. 1) are 
rather small, black, glistening, sub- 
globose or somewhat depressed, 
varying from 75 to 250 wu in diam- 
eter. When mature they are filled 
with spores, but those formed late 
Fic. 2.—Spores of Phyllosticta solitaria : : 
from twig cankers of the Ben Davis Jl! the season usually fail to ma- 
apple. Bentonville, Ark., May 25, f{ure. The period of maximum 
ae pycnidium production is in May 
on the twigs and in late June and early July on the fruit and leaves. 
Those on the leaves rarely produce spores. 
The spores (fig. 2) are hyaline, one celled, and when mature are 
filled with rather large, uniform-sized, often closely compacted 
granules. They are oval to subglobose and measure 8 to 10 by 5.5 to 
