tar spot
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DESCRIPTION This fungus is noticable on maple leaves when it matures and bursts out from within the leaf tissue. In late spring or early summer, it is not as noticable with pale spots on the leaves. As summer progresses, the spots enlarge and darken. Fallen leaves with the fungus will infect new leaves in the following spring. |
| HOST PLANTS Rhytisma acerinum (causing large blotches) and R. punctatum (causing clusters of smaller spots) infect maples. Other Rhytisma species infect other plant host species CONTROL In spring, some of the spores from fallen leaves will likely infect the newly opening leaves on the tree. Raking and destroying the autumn's fallen leaves will greatly help in reducing transmission of the disease. It may be unsightly later in the season, but it doesn't really cause damage to the tree. Fungicide sprays are expensive as they need to be very thorough and reach all infected areas. |