State-County Tree Pest Battle Gets a Mite Confusing

A little brown beetle from Australia that is killing Orange County’s eucalyptus trees has triggered a kind of reverse turf battle between county and state officials, with both sides saying the other should be responsible for dealing with trees infested by the pest.

The eucalyptus longhorn borer is a native of Australia that first was discovered in the United States at an El Toro eucalyptus grove in October, 1984. Since then, it has been found in other areas throughout Southern California.

Agriculture officials said the damage is not yet severe in the county. But there are jobs--such as thinning eucalyptus groves, caring for existing trees and replanting others--that have been largely ignored while county and state officials debate jurisdiction.

The county’s Legislative Planning Committee recently voted to propose new state legislation that would require the state Department of Forestry to care for infested trees.

Potential Fire Hazard

Until now, the only agency paying much attention to the problem has been the county fire department, which considers the growing number of dead trees a potential fire hazard.

The department said, however, that it does not have the financial or staff resources to care for trees or eradicate insects. Asst. County Fire Chief James Radley said: “Our position is that the state Department of Forestry is a state agency, and the insect has the potential of becoming a statewide infestation. We feel this is an area where they could lend assistance.”

But in meetings last spring, the state Department of Forestry told both Orange and Los Angeles counties that it does not have the authority to manage infested trees that are outside state forests or not of commercial value.

“That’s where the rub comes in,” said Brian Barrette, the forestry department’s staff chief for forest management in Sacramento. “It is basically a local problem.”

State legislation could change that, Barrette said, but that would involve more money from the state and establishing a new office for the agency in Orange County. Barrette and county officials said the cost of dealing with the problem has not been determined.

County entomologist J. Nicholas Nisson said there have been no studies to determine the longhorn borer’s population in the county or the extent of its damage. Experts have estimated, however, that hundreds of county trees have died because of burrows dug through the wood by the larvae of the longhorn borer.

If the county had money, Radley said, there are dead trees that should be removed now, even though the problem has not yet grown into a real--as opposed to potential--fire hazard.

He said the legislation proposed by the county is prospective, in that it anticipates a future fire hazard that would be severe enough to require immediate removal of the dead trees. Before that point is reached, Radley said, the debate over jurisdiction should be resolved by legislation.

Funding Research

Although it is not providing direct maintenance of the eucalyptus trees, the state forestry department is already paying for research at the University of California, Riverside, into pesticides that might be used to fight the longhorn borer. Riverside entomologists have also gone to Australia to try to relocate parasites from the insect’s natural environment that might keep its population under control.

For now, though, there is no direct effort to eradicate or interfere with the bug’s growing population. The fight against the longhorn borer has so far been mostly an educational process.

Researchers have found that the bug is generally fatal only to trees that are underwatered or otherwise stressed by their environment. So brochures have instructed homeowners on how to keep their trees healthy and warned people not to transport eucalyptus wood from infested areas to Northern California, where the trees are even more plentiful and no longhorn borers have been found.

EUCALYPTUS TREE OWNERS’ GUIDE To prevent beetle infestation, irrigate eucalyptus trees with a trickling hose over a 24-hour period every few weeks during the summer. If necessary, form a dirt basin around tree to hold the water. Trees in heavy clay soil may need longer soaking. The first sign of beetle larvae is a flat trail underneath the bark. Once there are half-inch, oval-shaped holes in the bark left by emerging adult beetles, the tree is probably infested and soon to die. Immediately remove dead trees, destroy the wood or take it to a landfill. For more information, call the Orange County Agricultural Commission at (714) 774-0284. Source: Orange County Agricultural Commission