2006-08-31 / News

Anthracnose fungus affecting tree leaves not lethal

By Michaela Kennedy

Some of the maple trees around the island appear to be turning their fall colors early this year, and some residents are already raking up the fallen leaves.

The dying leaves are not a sign of a cold winter to come, but rather a result of a fungus growth attacking the plants, according to local specialists.

Arborist Matt Largess confirmed a few days ago that a blight is affecting local maple trees. He said he has received telephone calls since early June from residents noticing symptoms varying from insect holes to leaves dropping.

Largess noted that the leaf spot, or leaf scorch, was mainly affecting Norway maples and sycamore trees more than native species. The formal name of the fungus is anthracnose, Largess said. "The red and silver maples don't seem to have it, or at least not to such a strong degree," he added.

Trees near Southwest Avenue and in the Mackerel Cove area seem particularly affected, and residents in Shoreby Hill have also reported signs of tree trouble, Largess said. He put the blame on the erratic weather this summer, with heavy rains early in the season followed by a dry hot spell.

According to a University of Rhode Island GreenShare fact sheet, anthracnose fungus enters twigs and small branches on trees and on fallen leaves. The fungus is active during periods of mild winter weather, forming cankers and causing twig dieback.

The fact sheet also notes that spores are released and disseminated by wind and rain to the young expanding shoots and leaves.

Volunteer gardener Richard Salzillo from the GreenShare program at the URI Cooperative Education Center in Kingston confirmed that many calls have come into the center in the last week concerning dropped leaves. Salzillo also confirmed that the fungus has caused leaf loss and weakened trees. "But it won't kill the tree," he stressed.

"The important thing is to clean up the fallen leaves to keep the fungus from spreading," both Largess and Salzillo advised.

Salzillo did not expect the blight to continue, since the spores die as colder weather hits. "Unless we get the same kind of weather again, we shouldn't see the problem come back next year," he said.

Largess also eased worries about permanent damage to the trees, but hinted that more problems could continue if affected trees were not properly cared for. In addition to cleaning up dead leaves on the ground, watering, and pruning out dead wood help the stressed plants, he said. He is against using fungicide sprays, however.

"A full deep-root fertilization in the fall is a good idea," he added.

With a look at the larger picture of plant life, Largess explained that blight problems are cyclical, and just about every species of arbor become stressed at one time or another. He cited the mite problem with spruce trees a few years ago as an example. "Trees have an uncanny ability to survive," he noted.

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