Abstract

McCAIN, A.H., C.S. KOEHLER, & S.A. TJSVOLD. 1987. Pitch canker threatens Calfornia pines. California Agriculture 41(11-12): 22-23.

In the summer of 1986, hundreds of Monterey pines in Santa Cruz County were found with serious branch dieback symptoms that did not fit the pattern of any disorder known in the state. Subsequent investigation confirmed that these symptoms were the result of a fungus known as Fusarium subglutinans. The most obvious symptom on Monterey pine is dead branch tips, but entire branches and even tree tops may be dead. A great deal of pitch often oozes from diseased plant parts. The canker is at the junction of dead and living tissue; it is sometimes sunken, yet the bark remains intact. The wood beneath the canker is resin-soaked and honeycolored. Affected trees become progressively worse in appearance, probably as a result of bark beetles exploiting declining tissues.

• © 1988, International Society of Arboriculture. All rights reserved.