Silky hakea (Hakea sericea) is an invasive alien plant from Australia which threatens vast areas of the fynbos biome, where it chokes out indigenous species and soaks up precious water. Control options have included slash-and-burn techniques and various biocontrols in the form of insects that feed on seeds and flowerbuds, or bore into stems. These methods are impractical or too costly in certain mountainous areas in the Western Cape, where dense stands of silky hakea have become well-established in regions inaccessible by foot on some of our own properties, such as Waaihoeksberg and Steenboksberg.
Now there is new hope in a novel application of a ‘mycoherbicide’, an indigenous fungus (Colletotrichum acutatum) which kills silky hakea by causing stem and branch cankers that exude large quantities of gum (gummosis). The gummosis fungus does not pose any threat to indigenous flora, or to other Hakea species.
Watch how the MCSA has been helping the ARC experiment with a novel technique of infecting silky hakea trees with a ‘gummosis’ fungus. The fungus kills silky hakea, but leaves indigenous flora unaffected.
This work is being done by the ARC (Agricultural Research Council), with assistance from WWF South Africa, The Drakenstein Trust and the MCSA.