Fusarium Wilt of Canary Island Date Palms

Fusarium wilt caused by Fusarium oxysporum f.sp. canariensis has caused the death of hundreds of Canary Island date palms, Phoenix canariensis, in Sydney where they have been used prominently in landscape plantings. The fungus is spread in soil, by transplanting palms and on contaminated pruning implements and possibly by seed, birds and insects. Vegetative compatibility groupings (VCGs) were used to examine the diversity and population structure of over 70 isolates of F. oxysporum f.sp. canariensis collected from different sites and different parts of individual palms within a site. Compatibility groupings showed two major VCGs limited to one site and a scattering of smaller VCGs throughout the Sydney region. Typically, frond isolates from the one site fitted into the one group while non-frond isolates (roots, soil and fruit) did not. A low proportion of seed isolates were compatible with the major (and presumably pathogenic) group, indicating seed transmission of the disease is possible. PCR analysis using primers designed to amplify the pathogenic group is in progress to both confirm VCG groupings and develop a rapid diagnostic test for the disease.