Incurable Fungus Attacking Historic Palms : Landscape: Fusarium wilt is killing about 40 trees that have lined Capistrano Beach streets since 1920s.

An incurable and fatal fungus is ravaging a group of historic date palms in Capistrano Beach and is turning once stately green fronds atop the trees into brown skeletons.

About 40 of the 250 palms, planted in the 1920s when the Doheny family developed the area, have been hit with the fungus known as fusarium wilt, according to Rick Still, parks superintendent for the city of Dana Point.

The deadly disease is usually passed on when pruning equipment is not properly sterilized, Still said. He said that pruning equipment can be sterilized by soaking it for five minutes in a 2.5% solution of hypochlorite. He said chain saws should not be used for trimming because they cannot be sterilized.

Exactly when the fungus was spread is unclear, but some residents said they believe the city, which contracts with trimmers to groom the palms, is to blame.

“As a homeowner, I’m upset,” said Mike Major, an arborist and landscape contractor. “I feel that the city is responsible and they need to correct the situation.”

The city first became aware of trouble in March. The trees, on a city right-of-way, are among those that line Avenida las Palmas and Calle Fortuna.

The city took over responsibility for maintenance of the trees last year after the Capistrano Bay Parks and Recreation District was consolidated with the city.

Still said it’s hard to tell if the 40 dying palms were all infected about the same time, but he suggested that varying conditions of the diseased trees means they were infected at different times.

Still said that some homeowners had hired their own tree trimmers in the past, and city-contracted crews most recently trimmed a batch of palms last fall.

“We have followed all the guidelines to keep from spreading the fungus,” he said.

The infected trees are as good as gone, experts said.

Henry Donselman, a former palm specialist for the state of Florida who now has a consulting business in San Diego County, said fusarium wilt is almost always fatal.

“Sometimes it’s a very slow progression, but it can’t be reversed,” Donselman said.

Donselman said the fungus, which has been limited to California so far, could incubate in a tree for six months to two years before symptoms show.

Doris Conroy, who lives in the neighborhood, said Friday that she was unaware of the fungus.

“It’s a shame,” she said, peering at the tree. “It’s pretty sad looking.”

Angela Duzich, a city code enforcement officer, said she was also saddened.

“They’re sick,” Duzich said. “They’re really sick, and there’s no cure for them. It breaks my heart.”

The city plans to send letters soon to neighborhood residents, warning them of the fungus and how to prevent its spread to other trees, Still said.

The cost to remove the trees and replace them will also be studied, he said.

Major estimated it would cost between $5,000 and $6,000 to remove and replace each of the 20- to 25-foot-tall palms, which originate in the Canary Islands.

Lynn Muir, former director of the Capistrano Bay Parks and Recreation Department, said he hopes that the city will change its trimming schedule to allow the palms more growth on top.

Muir, who is also the director of the International Palm Society, said the palms should only be pruned for their health, not aesthetics.

“The point is, they shouldn’t trim any green sections,” he said.