Resistance to pitch canker disease, caused by Fusarium subglutinans f.sp. pini, in Monterey pine (Pinus radiata)

Fusarium subglutinans f.sp. pini causes pitch canker, resulting in branch dieback and stem cankers, in many species of pine, Monterey pine has suffered extensive damage from pitch canker in both urban and native forests in California. The extent of lesion development differed significantly among Monterey pine individuals subjected to mechanical inoculations under field and glasshouse conditions. Lesion lengths resulting from inoculations of the same clone at different times or in different locations were highly correlated. The eight strains of F. s. pini known to occur in California did not interact differentially with the Monterey pine clones tested. Trees with limited lesion development did not sustain girdling lesions or branch dieback and hence may be considered resistant to pitch canker.