Tar Spot   (Rhytisma acerinum)


tar_spot.jpg (15736 bytes)Common Name(s): Tar Spot

Scientific Name(s): Rhytisma acerinum

Type: Fungus


Principle Host Trees & Shrubs:

Sycamore and other Maples (Acer species).


Description, Development & Diagnosis:

The fungus overwinters on fallen leaves. Fresh spores are produced in Spring which have a sticky coating. The spores attach themselves to the new leaves as they form. A raised, shiny black spot appears on infected leaves.


Significance:

Common. Can cause premature leaf drop but the vigour of the tree is rarely affected. Rarer in cities due probably to fewer fallen leaves left under trees.


Control:

Generally unnecessary. If a problem on ornamental species dispose of fallen leaves in Autumn to reduce spore levels in Spring.

Further Information.

2001 Chris Skellern. AIE.    Home  | News | A-Z Index  | Resources  |  Contact AIE  |  Terms of Use