Bugs Attacking Eucalyptus Spread to Street Trees

Calling it “a significant pest problem,” Los Angeles Public Works officials Friday joined the city parks department in fighting infestations of tiny pests attacking eucalyptus trees.

The bugs--redgum lerp psyllids--first discovered a year ago in El Monte, are now being found in street trees as well as in the parks, said George Gonzalez, chief forester of Public Works’ Street Tree Division.

The two departments have joined in a pilot program to release natural predators of the bugs and to inject insecticide into trees in areas of heavy infestation.

While the bugs have been discovered throughout the city, some of the heaviest infestations are in the San Fernando Valley, where vast groves of stately eucalyptus trees have thrived for decades in parks and along parkways, city officials said.

The Los Angeles Department of Recreation and Parks in May began a pilot program to fight the pest by releasing millions of ladybug beetles, which feed on the insects. The departments also plan to release lacewing larvae, a common predator insect, and to use micro injections of a low toxicity insecticide into the trees. The insecticide, which poses no threat to the public, travels into the leaves and kills the insects feeding on them.

The psyllids coat the leaves of certain varieties of eucalyptus with a hail-like, sticky substance that falls to the ground, sticks to shoes and creates a mess.

A species of wasp is a natural predator of the pest in Australia, where both the bugs and the trees originate. Entomologists have called for importing the wasps for use in the United States, but must first complete studies to ensure that the wasps pose no threat here. Those studies are expected to take up to a year.