The Polyphagous Shot Hole Borer (PSHB) has been detected in Perth and the Department of Primary Industries (DPIRD) and Regional Development has asked Perth gardeners to watch for symptoms of this pest. If it gets established in Western Australia, it would have a significant impact on our urban canopy.
The beetle, native to Southeast Asia, attacks a wide range of plants by tunnelling into trunks, stems and branches. PSHB has a symbiotic relationship with a Fusarium fungus, farming it inside the tree as a food source for the beetle and its larvae. In susceptible trees, the fungus kills vascular tissue causing Fusarium dieback and tree death.
There is a very helpful animation on YouTube produced by DPIRD which shows the effect on the tree and how to report suspected infestations. On the DPIRD website there is a map of the current Quarantine Area and a list of suburbs subject to the Quarantine Area Notice.
There is a link to the global host list of over 100 reproductive hosts and the WA host tree list.
Monitor trees and shrubs for symptoms including multiple entrance holes on the trunk or stems that are about the size of a ballpoint pen tip, bark discoloration, gumming, frass (or sawdust), crystalline foam (sugar volcanoes) exuding from the entry holes and tree wilting or dieback.
Report suspected PSHB damage online at mypestguide.agric.wa.gov.au, through the MyPestGuide Reporter App, by phone 08 93683080 or email: email@example.com
Images from the DPIRD website
This is intended as general information only. Please ask one of our horticulturists for specific advice for your situation.