Blight Hits Thousands of Acres : Fungus Suspected in Die-Off of Chaparral

Scientists say a fungus may be the cause of a mysterious, spreading blight that has killed thousands of acres of chaparral and created dangerous brush-fire conditions this summer from Santa Barbara to San Diego.

Federal researchers say a microorganism called Botryosphaeria has been discovered in brush that was weakened by drought three years ago. They said the fungus can be fatal to withering shrubs that are battling to recover from the drought.

Officials confirmed their discovery Thursday as they disclosed that large patches of dying chaparral have been found in Southern California.

The outbreak, called a “dieback” by foresters, was first noticed nearly two years ago in the San Gabriel Mountains north of Los Angeles. By early 1985, it had spread to the Santa Monica Mountains.

Foresters speculate that up to 500,000 acres of brush may now be affected, although the dieback is not as pronounced this year as it was in 1985.

U.S. Forest Service researchers said the dark, splotchy fungus was found earlier this year in the stem section of a wild lilac plant taken from the San Dimas area. It was identified by a laboratory in Sacramento last month.

“It’s a breakthrough in that we have a name for it and it is something we can look at now,” said Paula Jenks, an ecologist for the Forest Service in Riverside. She said there is no known way of controlling the fungus, however.

Robert Lockwood, another researcher at the federal Pacific Southwest Range and Experiment Station in Riverside, said scientists will investigate whether the fungus is the cause of the dieback or merely a beneficiary of the stressed condition of the chaparral.

He said such a greenhouse study will probably not be undertaken until after mid-October, when researchers at the station complete a previously scheduled controlled burn project in Lodi Canyon north of San Dimas. That 1,200-acre fire will be part of research into the “nuclear winter” problem being conducted by 13 federal agencies.

Los Angeles County Fire Department officials, meantime, said they plan to monitor plots of brush south of the San Fernando Valley in hopes of determining the rate of spread of the fungus.

Fire Capt. Scott Franklin said officials will look for fungus in the Stone Canyon area between Sherman Oaks and Bel-Air and in the Mulholland Crest area between Woodland Hills and Topanga Canyon.