214 MANUAL OF FRUIT DISEASES 
The disease may first be observed on the white pine (Fig. 57) 
in the spring from April to early June. The stem or branches 
are often girdled and the portion above dies. Most young 
trees die in a relatively short time; others live for some time, 
but even old stems finally succumb, the tree eventually break- 
ing at the lesion. The disease in its early stages shows peculiar 
Fic. 55. — European currant-rust; uredinia on lower surface of black 
currant leaf. 
fusiform, or spindle-shaped, swellings which taper upward. 
These are usually found on wood at least three years old. When 
a swelling is first noticeable, small transparent spots appear 
which develop into blister-like pustules surrounded at the base 
by a translucent spot, whence the name blister-rust. These 
pustules break open and drops of sweet, honey-colored fluid 
exude. Later, spore-pustules break through the bark. These 
are small, scattered, and from them orange-colored masses of 
spores push forth through the break in the bark (Fig. 57). 
