Biosecurity Alert: Polyphagous Shot-Hole Borer

City of Cockburn is working with the Department of Primary Industries and Regional Development (DPIRD) to help stop the spread of the invasive pest Polyphagous shot-hole borer (PSHB) Euwallacea fornicatus.

PSHB attacks a wide range of plants by tunnelling into trunks, stems and branches. The beetle farms a Fusarium fungus, which they spread inside the tunnels, disrupting the flow of water and nutrients. This can result in tree dieback and death.  

PSHB is a serious issue across the Perth metropolitan area and a Quarantine Area Notice (QAN) is in place to support DPIRD’s ongoing surveillance program to stop the spread of the pest. The Quarantine Area (QA) has been extended to 25 local government areas, including the City of Cockburn. 

• Movement of wood and plant material within the QA is permitted
• Wood must be chipped to pieces that are less than 2.5cm in diameter before leaving the QA 
• Living plants with woody stems greater than 2cm in diameter must not leave the QA 
• Machinery used to handle green waste must be cleaned of wood material prior to leaving the QA 
• A permit is required if these conditions are unable to be met. 

The borer does not affect grass so lawn clippings can be disposed of as normal. 

Green waste can be placed on your verge for collection as normal, but please check your trees and plants for any unusual symptoms before you start pruning. Read more below.

Detection is difficult as they are very small – about the size of a sesame seed. However, there are several symptoms that indicate a tree may be infested: 

• Beetle entry/exit holes roughly the size of a ballpoint pen tip  
• When pruning branches or inspecting fallen branches, check for evidence of galleries caused by tunnelling beetles  
• Discoloration/staining  
• Thick resin or sap  
• Frass or “noodles” caused by tunnelling may be seen on the tree exterior, indicating a high level of infestation  
• Sugar volcanoes, crystalline foam exuded from entry/exit holes, are a common sign of infestation on Avocado trees  
• Dieback and tree death.