The fungus releases orange spores from the pustules and these are spread by the wind to initiate new infections on leaves. In late summer and early autumn these pustules produce dark, overwintering spores, but over-wintering spores are not usually found on fuchsias. These survive over the winter on infected plant material and germinate in the spring to release spores which can only infect Abies, where the fungus goes through a further cycle of development, releasing airborne spores which can reinfect fuchsias. However as mentioned above, the disease is probably present in fuchsias all year anyway.
The rust fungi are described as biotrophs: they grow within the living tissues of the plant and extract nutrients from the cells over an extended period. However, although they do not kill tissues rapidly, heavy attacks by rusts can cause tissues to collapse and die prematurely and this is the case for fuchsia leaves. This leads to a great loss of vigour and an unsightly plant.