FARMERS' BULLETIN 742. 



FIG. 4. Diagram indicating the life circuit of the causal fungus of the white-pine blister rust, a, Blisters 

 on pine in May and early June, from which the disease spreads to currant or gooseberry leaves and pro- 

 duces the early summer stage, 6; thence it may spread to another currant leaf and produce there a second 

 crop of the early summer stage, c, or it may produce the late summer stage, d; in this stage, in the fall, it 

 infects neighboring white pines, which may or may not include the pine (a) which bore the blisters that 

 started the outbreak the preceding spring. 



