302 MANUAL OF FRUIT DISEASES 
In the spring, March and April, conidia coil out in long, 
reddish brown masses from the fruiting bodies already men- 
tioned. The process is favored by quiet, damp weather, and 
it takes place in a few hours following the advent of favorable 
conditions. The spores are scattered by the wind, rain and 
probably by birds. Within twenty-four to forty-eight hours 
germination occurs, and the germtube enters the bark through 
a bud or through a wound of any sort. The germtube soon 
develops a copious growth of mycelium which is found between 
the outer bark and the wood in grayish mats. Numerous 
gum pockets are formed in the cambium and inner bark; 
many of these unite to form larger ones. The gum thus formed 
exerts a pressure on the bark, which is ruptured, and an exuda- 
tion follows. This gum-flow, sometimes referred to as gum- 
mosis, is characteristic of the peach and other stone-fruit trees 
when injured (sée page 303). 
The fungus may grow down the twigs into the branches, 
and in this manner large limbs and even trunks become in- 
fected. On all affected parts pycnidia are developed in abun- 
dance. They occur most abundantly, however, on twigs, while 
perithecia are most common on the limbs and trunks; the 
two kinds of fruiting bodies may be intermingled on trunks 
and larger limbs. Ascospores are discharged from January 
to April, while conidia, as noted above, are disseminated in 
March and April. 
Sometimes the advance of the fungus is halted, and affected 
_parts may outgrow the disease. Frequently, however, the 
fungus remains active until late in the fall; its progress is 
then interrupted by the first freezing weather. With the return 
of favorable weather the fungus renews activities and the 
mycelium spreads. 
Control of die-back. 
The fungus is ever-present on stone-fruit trees, and shows a- 
marked preference for trees already in a poor condition as a 
