SUSCEPTIBILITY OF 5 LANDSCAPE PINES TO PITCH CANKER DISEASE, CAUSED BY FUSARIUM SUBGLUTINANS F SP. PINI

Pitch canker, caused by Fusarium subglutinans f. sp.pini, causes branc h dieback and stern cankers in many species of pine. Monterey pine (Pi nus radiata D. Don), one of the most widely planted pines in the world , is extremely susceptible to pit ch canker. Four other pine species, which might serve as alternatives to Monterey pine in landscape settin gs, were found to be relatively resistant, based on the size of lesion s resulting from branch inoculations under greenhouse conditions. Of t hese species, Japanese black pine (P. thunbergiana France) was the mos t resistant, followed by Canary Island pine (P. canariensis Sweet ex K . Spreng), Italian stone pine (P. pinea L.), and Aleppo pine (P. halep ensis Mill.). Consistent with these findings, a field survey conducted in Alameda County, Calif., revealed Monterey pine to have the highest incidence of infection, with significantly lower levels in Aleppo, Ca nary Island, and Italian stone pines. Japanese black pine was not obse rved in the survey area.