Pitch canker is a disease caused by a fungus (Fusarium subglutinans pini). This disease was first found in California in 1986 when the fungus was isolated from naturally infected Monterey pines in Santa Cruz County. Since that time pitch canker has been found in isolated locations along the coast from Mendocino County to San Diego County. On the Central Coast infected trees can be found from Cambria to Carpinteria.

Usually, the first symptoms of pitch canker are branch tip dieback on the top and sides of the tree. Tip dieback is usually accompanied by the presence of copious amounts of resin exuding from infected branches, and the tree trunk covering the bark with pale yellow streams of pitch.

At present, the host range of the pitch canker fungus is mainly in pine tree species. Monterey pine is most commonly infected, but Aleppo, Bishop, Canary Island, Coulter, Digger, Italian stone, Knobcone, Ponderosa, Shore, and Torrey pine, plus Douglas fir are known susceptible hosts for this disease. All the above species have been found naturally infected in the field.

Several cone beetles and twig beetles have been associated with pitch canker and are suspected of being vectors of the pitch canker fungus.

Once a tree is infected with pitch canker, it will remain infected. At present, there is no cure. In wild pine tree populations a range of susceptibility has been noted.

Researchers are presently selecting highly resistant and immune individuals. These trees and their progeny will be tested, and disease-free offspring will be used to repopulate pine forest areas that have been devastated by pitch canker.

Diseased pine trees should be removed from the landscape. Wood from diseased trees should be chipped and composted or burned. DO NOT cut and store pitch canker-infected wood for firewood. The fungus can continue to live in infected wood for several years, and wood piles can be a source of fungus for new infections. Also do not transport pitch canker-infected wood to other locations.

Pitch canker is a serious, relatively new disease of pines in California. Infected trees should be destroyed to slow the spread of this pathogen as much as possible.