A canker, swollen resinous lesion, develops and continues to grow as long as the branch remains alive. If a canker girdles a branch, the movement of water and nutrients is blocked and the branch dies from that point outward. The first reproductive structures, pycnia, appear on infected pine branches 2 to 4 years later. Pycnia exude sticky drops of yellow fluid. The next reproductive structures, aecia, develop in the same region in the spring 3-6 years after initial infection.
Aecia are pale yellow to bright orange blisters.
Aecia produce spores which are wind blown to the alternate hosts. Aeciospores infect the underside of currant or gooseberry leaves where the third type of reproductive structures, uredia, develop. Spores produced by uredia can infect more Ribes leaves throughout the season, thus increasing the number of infections. During late summer and early fall, brown hair-like reproductive structures called telia develop near the uredia. Teliospores germinate and form another reproductive structure called basidia.