Council’s Help Is Sought in Tree Pest Fight

The Los Angeles city government, already trying to cope with the effects of the state’s war on the Medfly, will be asked to do battle against another pest, a beetle that is killing Southern California’s drought-weakened eucalyptus trees.

On the eve of National Arbor Day, City Councilwoman Joy Picus stood in the shade of an endangered eucalyptus in Canoga Park on Thursday and said she will ask the council next Tuesday to approve emergency legislation establishing a task force to combat the eucalyptus longhorn beetle.

She criticized the state for focusing on the Medfly problem, saying other pests are being ignored.

“Our state has spent some $30 million in Medfly eradication. They spend about $10 million in other pest eradication,” she said, accusing the state Department of Food and Agriculture of failing to protect the trees.

“We don’t want to lose any of these trees which make us feel better. Trees give us shelter, air and beauty. Especially in an urban environment, we need to be doing everything we can to save life-giving trees and to plant even more.”

The task force she proposed would consist of representatives from three city agencies, the Bureau of Street Maintenance, the Department of Recreation and Parks, and the Department of Water and Power. It would be charged with determining the extent of the beetle problem and recommending “environmentally benign ways” to control it, Picus said.

The longhorn beetle found its way to Orange County six years ago from Australia, native land of both the trees and its insect parasite. Until recently, California eucalyptus trees flourished in the absence of natural enemies, becoming the most widespread non-native tree species in the state.

“We never invest in the kind of research” that is needed when pests first appear, Picus said. “The pest attacks and six years later, we’re wringing our hands.”

The pest has killed about 550 of the 250,000 city-owned eucalyptus trees and about 1,200 more are believed to be infected, said Richard Ginevan, chief parks supervisor for the San Fernando Valley. Ginevan appeared with Picus at a news conference in Shadow Ranch Park, where some of the first eucalyptus trees in the state are believed to have been planted in the 1860s by a landowner who imported them to cheer up his homesick Australian bride.

Since its discovery in Orange County, the longhorn beetle has spread to Catalina Island and Los Angeles, San Bernardino, Riverside, Ventura and San Diego counties. But because it takes at least one year before a tree shows signs of beetle infestation, city officials are unsure how many privately owned eucalyptus trees are under siege in Los Angeles.

The trees’ natural defense is to drown the beetles in sap, but several years of drought have reduced their sap supply. The brownish-black longhorn beetle, which grows up to 1 1/2 inches long and has cream-colored zigzag markings on its wings, lives under the tree’s bark, making chemical spraying useless.

Scientists at UC Riverside have been experimenting with a species of Australian wasp, which preys only on the larvae of the longhorn beetle. The wasp also keeps the beetle population under control in Australia.

After hatching, the beetle larvae bore tunnels in the wood--sometimes more than an inch wide and several feet in length--and eat the tree’s mushy cambium, the layer between the bark and wood that carries nourishment. The trees die of starvation.

It costs the city more than $100 to dispose of each dead tree, Ginevan said. “We can’t sell this firewood,” he said. “We have to bury it at the landfill” to prevent the beetles from spreading.

It is against state law to transport infected wood.

Picus said she has a personal stake in seeing the eucalyptus trees survive. Thirteen years ago, she helped block development of land bordering Shadow Ranch Park because the development would have harmed the trees, she said, “and I am not about to let the eucalyptus trees die.”