PEACH DISEASES 317 
of conidia’ are developed. From the mycelium erect stalks 
are formed which bear conidia in chains at the tip. These 
stalks are the conidiophores; they, with their conidia, add to 
the felt-like, whitish growth, covering the diseased portion. 
The conidia are scattered throughout the summer, and those 
which fall on peaches will, under favorable conditions, germinate 
to start a new mildew spot. From the germtube a dense mat 
of mycelium develops. At intervals over the hyphal system, 
sucker-like bodies, called haustoria, are sent into the epidermal 
Tic. 84. — Peach-mildew on fruits. 
cells. These haustoria are the feeding organs of the fungus, 
and as a result of their activity the attacked portion becomes 
brown and cracked. 
After midsummer perithecia may be developed. These 
bodies when formed carry the fungus through the winter, but 
as a Tule they are extremely rare. When found they occur 
more on twigs than on leaves. In those cases where perithecia 
do not develop, it is thought that the fungus hibernates as 
mycelium in the buds. 
The fungus thrives best in a warm, moist, shaded location. 
Trees that are closely planted are more likely to be affected ; 
