PITCH CANKER OF PINES - A CONTEMPORARY REVIEW

Fusarium subglutinans f. sp. pini (F. s. pini) has, for many years, be en recognised as the causal agent of pitch canker of pines in the sout hern United States. Recent occurrences of the disease in new geographi cal areas has led to a revival of pitch canker research. F. s. pini ca n be separated from other non-pine isolates of F. subglutinans in its ability to attack pines, as well as on the basis of its genetic and mo lecular structure. Sub-specific populations that are essentially biolo gical species may, therefore, exist within F. subglutinans. Pitch cank er has been reported from four new geographical areas, including Calif ornia in the United States, Mexico, Japan and South Africa, during the course of the last eight years. Incidence and spread of pitch canker in Mexico suggests that the country might be regarded as a possible ce ntre of origin of F. s. pini. The population structure of F. s. pini i n Florida, where the disease is well established, is genetically diver se and represents a large number of vegetative compatibility groups (V CGs). In California and South Africa, where the fungus is believed to have been introduced recently, a small and a large number of VCGs have been reported in the former and in the latter respectively. The popul ations in California and South Africa suggest that the pathogen has mo st likely been introduced from different sources. It is expected that pitch canker will spread to new areas and become more severe in future .