Leaves are changing...

[tropicana]

This story comes out from the town of London Ontario, about 100 miles west-south-west of Toronto/ 120 miles west of Buffalo New York.

SUN AUG 22nd 2004
Falling leaves

The blight hitting maple trees isn't deadly, but it will make London less colourful this fall.

A blight on many of the region's maple trees is again bringing leaves down early this summer. And it's likely to take some of the shine off the dazzling colours that paint the area's treescape this fall.

The blight is not new. Anyone with maples will have noticed the drifts of dry, crispy leaves blowing around -- just as they did late last summer.

And since about one-quarter of the city's roughly 160,000 trees are maples, the effect on the fall palette can be stark.

The problem with the maple trees are tar spots, the common name for a fungus called rhytisma acerinum.
The blight is causing leaves to fall before they change colour, McGauley said.

But apart from a dull fall, the black blotches covering maple leaves shouldn't cause too much worry, he said.

"It really doesn't cause any significant health problems for the trees other than they may grow a little more slowly this year," he said.

Londoner Mike Anderson has similar assurances after he noticed the blight in a towering maple in his front yard and called in a tree service.
"The day after I cut the lawn, it's full of dead leaves again," he said. "It's kind of like the end of October."

Anderson said his big maple -- perhaps 40 years old -- has broken out in the spots for the last three years, which left him worried there might be something wrong that would force him to cut the tree down.

The service he called in told him about the blight -- and that he had no reason to fret.

"Apparently, this will work itself out," he said, sounding relieved. "It may take a couple of years."

The disease infects leaves in the spring, when previously infected leaves rotting on the ground release tiny spores in the air currents, McGauley said.

The infection progresses inside leaves all summer, he said, with red and yellow spots darkening to black by July and August.

There's not much people can do to curtail the spread of the disease, he said.

"This is an infection that is airborne and native to this part of Ontario."

The tar spots have infected trees as far as Barrie, Ottawa and Windsor, McGauley said.

"The only way this is going to go away is when we have a fairly strong climatic disturbance," he said, such as a very dry spring or harsh cold snap.

The blight seems more prevalent in London's northwest, but only because there are more maple trees there, McGauley said.

The tar spots also appeared last September, along with another disease known as Anthracnose.

Becky Moule of Arbortech Professional Tree Care said she gets a couple of calls a day from people concerned their trees -- Norway maples are hardest hit -- might die from the tar spots.

That's unlikely, but she said years of drought and tar spots aren't good for trees. "It's not healthy for a tree to be losing its leaves this time of year. If they're stressed out, then insects and disease come in."

Her advice to homeowners is not to compost or mulch the spotty leaves, because that risks spreading the problem.

"Just rake them up and . . . get rid of them," she said.

Moule said property owners need to take a longer-term view and avoid planting the same kinds of trees all over the city all the time.

"We've got to start being more diversified."

Moule said the cool, wet weather that's been ideal for growing tar spots also has had an upside: After five years of drought, the trees have needed the rain.

-justin-