Pathogenicity of monokaryotic and dikaryotic mycelia of Ganoderma boninense on oil palm seedlings and germinated seeds in Malaysia

Pathogenicity tests were carried out on oil palm seedlings and germinated seeds using monokaryotic and dikaryotic mycelia in order to investigate the indirect role of basidiospores in initiating basal stem rot disease in oil palm. The pathogenicity tests conducted showed that monokaryotic mycelia were not able to cause infection while reconstituted dikaryotic mycelia could initiate basal stem rot infection on both oil palm seedlings and germinated seeds. The severity of the disease symptoms on both seedlings and germinated seeds was found to be related to the size of the inoculum, with larger inoculum resulting in more severe symptoms. The present study indicates that monokaryotic mycelia which originated from germinating basidiospores could colonise any available substrate and that basidiospores therefore indirectly played a role in basal stem rot infection in oil palm fields.