Experts Plot Against Bugs Ravaging Eucalyptus Trees

War has been declared by cities and scientists against a tiny beast that is ravaging eucalyptus trees in Orange County and elsewhere across the state.

Alarmed by a population explosion among red gum lerp psyllids, insects that leave trees bald and sickly and excrete a sticky goo onto sidewalks and cars, nearly 100 scientists, city representatives and pest control experts converged in a Highland Park community center Wednesday to share information and strategies.

In the next month, Los Angeles plans to form a multi-agency task force to coordinate a regional attack on the one-eighth-inch insect, said George Gonzalez, chief forester for the Department of Public Works.

Red gum psyllids, first identified in Australia in the 1960s, were discovered in California about a year ago. Found first in El Monte, they have spread into San Diego, the Inland Empire and farther north than the Bay Area.

Although the insects have not yet killed any trees in the state, they cluster on leaves, block photosynthesis and cause a massive shedding of leaves. Young insects are covered by white, armor-like coverings called lerps that shield them from natural predators and common insecticides. An infected tree’s leaves are covered with lerps, which, from afar, look like a bad case of dandruff. Infected trees are more prone to attacks by insects such as borer beetles and diseases such as root rot that can kill them.

The psyllids are not as economically menacing as the medfly, which can destroy fruit crops, said Rosser Garrison, an entomologist with the Los Angeles County Department of Agricultural Commissioner/Weights and Measures. But there has been an enormous public outcry, because the damage they wreak is so visible.

At the Arboretum of Los Angeles County in Arcadia, which has the largest eucalyptus collection outside Australia with about 200 species and 1,000 trees, about a third of the eucalyptus--and 100% of the red gum variety--are infected with psyllids, said biologist Jerry Turney. The insects also are starting to attack a few other eucalyptus species.

In Lake Forest, where the infestation is among the worst in Orange County, residents must cover their cars and patio furniture, or move them into their garages, to avoid the messy residue that the bugs leave behind.

Countywide, authorities are receiving dozens of calls a day from homeowners and others stumped about what to do.

The most promising solution is a breed of tiny Australian wasps that feed exclusively on red gum psyllids, said Donald Dahlsten, professor and associate dean of the College of Natural Resources at UC Berkeley. Within the next few weeks, he will go to Australia to bring the wasps--which do not harm humans--to California.

But it could be months, perhaps a year, before the wasps clear state and federal regulatory hurdles, he cautioned, adding that even then, there’s no guarantee that what works in Australia will work here.