Spot on Aspen
Description and Signs of Infestation"
first symptoms of ink spot appear in late spring to early summer
as tan to brown areas of the upper leaf surfaces. Concentric,
discolored ring patterns may become visible as the fungus advances
through the leaf. Infected leaves may be totally brown by mid-summer
while adjacent uninfected leaves remain green. Raised black bodies
begin to appear on affected brown leaves. These hard masses of
fungal material are oval shaped and nearly ¼ inch long.
These are the "ink spots" which give the disease a characteristic
"shot hole" effect on leaves that remain on the tree.
This disease is especially prevalent in dense aspen stands. Early
defoliation may cause reduced growth damage.
Spread of Disease:
The hard fungal tissue masses that fall from infected leaves are the overwintering stage of the fungus. Wet spring weather stimulates spore production. Spores are blown and splashed from the ground to developing leaves. Ink spot rarely reaches epidemic proportions because the fungus completes only one infestation cycle per year.
Simple rake, bag, and dispose of the fallen leaves.