Common on Coast, Tree Disease Found in Sierra

Pitch canker disease, which has plagued coastal Monterey pines for nearly 20 years, has been found in the Sierra Nevada.

It has so far been detected in a single spot, an orchard in the Eldorado National Forest east of Sacramento, and the Sierra environs are not as hospitable to the fungal disease as the coast. But if it becomes established in the range, pitch canker could threaten some of the most prevalent species, such as ponderosa pine.

“While there is no immediate cause for alarm, we are concerned about the possible spread of spores by wind or insects, as well as by movement of infested soil and plant materials,” Julie Lydick, the U.S. Forest Service’s assistant director for state and private forestry in California, said in a statement. “We are working with Forest Service and UC Davis researchers, the state of California and the forest industry to survey and monitor for pitch canker, determine the scope of the threat and find ways to protect trees in the Sierra.”

First discovered in California in 1986, the pitch canker has damaged native stands of Monterey pine as well as ornamental plantings from Mendocino to San Luis Obispo counties. The disease produces oozing cankers and causes branches to die back, eventually killing trees.

The Sierra detection, announced Wednesday, was made late last year when a Douglas fir cutting from the Badger Hill seed orchard aroused suspicion in New Zealand, where it had been shipped.

Douglas fir is not particularly susceptible to pitch canker but could act as a carrier for the disease, said UC Davis plant pathology professor Thomas Gordon.

The fungus likes relatively moist conditions, and for much of the year the Sierra is too dry or too cold for it to easily spread, he said. No pesticide treatments are effective in controlling it.