Tree Fungus is Widespread

BAR HARBOR — A fungal disease that is affecting maple trees downtown has become endemic to the area and is expected to return annually, a University of Maine scientist said this week.

The tar leaf spot disease, caused by the Rhytisma fungus, is affecting Norway, red, silver and sugar maples. The disease causes black, tar-like spots on maple leaves by the middle of the summer. Leaves with multiple infections eventually turn brown, dry up and drop from the trees.

The problem is largely an aesthetic one, although it can hasten the demise of  unhealthy trees, UMaine horticulturist Kate Garland said.

“It definitely doesn’t help the tree at all, but in most healthy trees it doesn’t cause death,” she said.

The town has posted an advisory on its website asking people to rake up the leaves as they fall and dispose of them at the municipal lawn and leaf compost facility on the Crooked Road. Temperatures in the compost pile there should be high enough to kill the fungus, public works director Chip Reeves said.

Wet spring weather over the past several years has provided the perfect climate for the disease to spread, Ms. Garland said. The fungus became prevalent in 2009 and has become a widespread problem across the state, she said.

“We’re expecting it to be back every year at this point,” she said. “We just kind of hope for a dryer season to keep it at bay.”

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Robert Levin

Robert Levin

Former reporter Robert Levin covered the people, businesses, governmental and nonprofit agencies of Bar Harbor. [email protected]