Impact of Pitch Canker on Ornamental Monterey Pines in Santa Cruz County, California, U.S., 1987-2000    (View PDF)

Donald Owen and David Adams

Abstract: Long-term observations of ornamental Monterey pine (Pinus radiata) showed that pitch canker severity varies considerably from one tree to the next and over time. Most Monterey pines proved susceptible to the disease, but many sustained only light to moderate levels of infection and some never developed any disease symptoms. We developed a rating system that proved useful in assessing pitch canker's impact. Although the majority of trees sustained heavy levels of infection, mortality was not a foregone conclusion for even the most heavily damaged trees. After an initial outbreak of pitch canker activity, the incidence of new infections decreased and eventually dropped to an undetectable level. Trees are now recovering in the absence of new infections. Application of this information will contribute to better predictions of disease impact. It should not be presumed that pitch canker will necessarily result in a high rate of mortality among Monterey pines.

Keywords: Pitch canker; Monterey pine; disease impact; disease rating; Fusarium circinatum; F. subglutinans f.sp. pini; Pinus radiata.

https://doi.org/10.48044/jauf.2001.033