Ink Spot on Aspen

Quick Facts:

  • The fungus "ciborinia" causes a leaf disease of aspen commonly known as INK SPOT.
  • Ink Spot decreases the tree' aesthetic value and can cause premature defoliation. If the outbreak becomes severe, the general health of the tree can be affected.
  • Raking and disposing of leaves and pruning out branches with cankers will reduce future disease occurance.

Description and Signs of Infestation"

The 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.

Ink Spot on Aspen Disease Cycle

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.

Control:

Simple rake, bag, and dispose of the fallen leaves.