A global climatic risk assessment of pitch canker disease

Abstract

Pitch canker is a devastating disease of Pinus spp. and Pseudotsuga menziesii (Mirb.) Franco. The pathogen responsible for this disease, Fusarium circinatum Nirenberg & O'Donnell, has spread to many countries within the last three decades. The susceptibility of the widely planted commercial species Pinus radiata D.Don to this pathogen has been of concern to pine forest industries worldwide. Using the process-based distribution program CLIMEX, the global risk of pitch canker establishment was predicted based on a number of climatic variables. The predicted risk of pitch canker establishment by CLIMEX fit well with regions known to have the disease, such as the southeastern United States and Spain. Conversely, the model predicted that the climate in California was not optimal for pitch canker, which fits with the observed lower frequency of natural infections and the strong association with insects in this region. Likewise, Chile, which is known to have F. circinatum in the nurseries but not in the plantation forests, was also predicted to have marginal to suitable climatic conditions for pitch canker establishment. Regions of China, Brazil, Australia, and New Zealand were predicted to have optimal climate conditions for disease establishment. Thus, continued strict quarantine regulations are recommended to prevent the establishment and spread of this pathogen in these countries.