Long spring leaves trees with nuisance disease
The area’s London planetrees, like these trees at Borah Elementary School in Coeur d’Alene, are infected with the nuisance disease called anthracnose. While not fatal, the disease can weaken the structure of branch attachments and cause trees to become exposed to other pests and diseases that could cripple or kill the sycamore hybrids.
CRAIG NORTHRUP/Press
While Coeur d’Alene — along with the rest of the country — grapples with the COVID-19 pandemic, some of the city’s trees are fighting off a less-serious but noticeable disease of their own.
The area’s London planetrees, a common hybrid connected in lineage to sycamores, are in the midst of an anthracnose outbreak: a disease that can disfigure the trees and weaken their immune systems. London planetrees often shed their lower leaves as a result of anthracnose, which is prompting concerned citizens to call the city.
“This originally came to me in late May or early June,” Coeur d’Alene urban forester Nick Goodwin said. “We’ve gotten several calls about it. Generally, planetrees grow out of (the disease). It’s not something that always has to be treated. It’s not a fatal disease. But we’ve seen some severe cases this year, and it’s been pretty widespread.”
Widespread, Goodwin explained, because of the unusually cool spring weather that crept into the summer months.
“It was a really cold, wet, long spring,” he said. “When you have that, the wind and rain promotes the spread of fungus. This year, we had that long, non-stop, cool, wet, rainy weather that helped spread it along. As a result, I’ve had some people say this was one of the worst infections they’ve ever seen, and it was textbook Sycamore anthracnose.”
By itself, the disease is rarely fatal to trees, but Goodwin said it can leave lasting, long-term damage that could contribute to its eventual downfall if left unaddressed.
“What you’ll see is a twig dieback,” Goodwin said. “It can weaken the tree, and once the tree is structurally weakened and defoliated, a different pest can come in, and maybe that pest can get the tipping point.”
“I don’t want to alarm the public, because I don’t think we’re going to see a large die-off,” he said. “But I want people to know that there are things we can do to aid the health of our trees.”
Most crucially, he said cleaning up leaves and destroying infected leaves is the most important thing. After that, brush away the fallen twigs. After that, if the problem persists, there are sprays out there that can alleviate the problem.