A Comparison of Host Susceptibilities to Native and Exotic Pathogens in Forest Tree Ecosystems

Abstract

Forest tree ecosystems are in danger of being disrupted by novel pathogens. It is important to examine factors that influence host susceptibility to these pathogens. There are three main components that contribute to host susceptibility: pathogen specific defense mechanisms, genetic bases, and pathogen generic defense mechanisms. Different susceptibilities can be found with varying tree and pathogen species and not every combination of host species and pathogen species will be influenced by the same factors. This review explores how different host tree species react to native and exotic diseases that affect their respective species. It has been determined that Eucalyptus globulus and Corymbia citriodora ssp. variegate show a form of pathogen-specific defense mechanisms to the native diseases Teratospheaeria sp. and Quambalaria pitereka respectively, with strong susceptibility to the exotic disease Austropuccinia psisii. Alnus glutinosa, however, shows that there is a genetic basis for pathogen resistance to Phytopthora uniformis and Phytopthora x alni. Lastly, Pinus radiata showed a generic form of pathogen defense towards Fusarium circinatum.