Latent infection by Fusarium circinatum influences susceptibility of monterey pine seedlings to pitch canker

Abstract

Pitch canker, caused by Fusarium circinatum, is a serious disease affecting Pinus radiata D. Don (Monterey pine) in nurseries, landscapes, and native forests. A typical symptom of pitch canker is canopy dieback resulting from girdling lesions on terminal branches (Gordon et al. 2001). More extensive dieback can result from coalescing lesions on large branches or on the main stem of the tree. The severity of disease depends, in part, on susceptibility of the individual tree. Some will suffer no more than a few infected branch tips, whereas others sustain extensive damage and may ultimately die from the disease, often in conjunction with other forms of stress. However, some trees that become severely diseased eventually recover, with the absence of new infections attributed to systemic induced resistance (Gordon et al. 2011). To date, induced resistance in Monterey pine has been examined only in mature trees, but the disease can also affect seedlings, with potentially significant impacts on regeneration. Although the pitch canker pathogen can be a cause of mortality in seedlings, those that are not killed may remain infected without showing symptoms (Gordon et al. 2001, Storer et al. 2001). The present study was undertaken to determine if seedlings with symptomless infections manifest systemic-induced resistance to pitch canker.

Parent Publication

• Proceedings of the fourth international workshop on the genetics of host-parasite interactions in forestry: Disease and insect resistance in forest trees

Citation

Swett, Cassandra L.; Gordon, Thomas R. 2012. Latent infection by Fusarium circinatum influences susceptibility of monterey pine seedlings to pitch canker. In: Sniezko, Richard A.; Yanchuk, Alvin D.; Kliejunas, John T.; Palmieri, Katharine M.; Alexander, Janice M.; Frankel, Susan J., tech. coords. Proceedings of the fourth international workshop on the genetics of host-parasite interactions in forestry: Disease and insect resistance in forest trees. Gen. Tech. Rep. PSW-GTR-240. Albany, CA: Pacific Southwest Research Station, Forest Service, U.S. Department of Agriculture. pp.159-161.