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 QA was extended on 6 September 2024 to cover the entire Perth Metropolitan area, extending across 30 local government areas.

The QA encompasses two zones.

• Zone A covers an area with high numbers of infested plants and has intensive control activities, such as plant removal, underway. This zone has more restrictions on the movement of high-risk materials.
• Zone B covers an area with fewer to no infested plants and has heightened surveillance underway to identify and control any new infestations discovered. This zone will help create a buffer between areas of high infestations and the rest of WA to further protect our flora.

The City of Cockburn is in Zone A.

Movement restrictions apply to green waste within the Perth Quarantine Area as follows:

Quarantine Area Zone A
Green waste over 2.5cm:

• can be moved into Zone A

• can be moved within Zone A

• cannot leave Zone A

• any machinery used to handle wood and plant material must be cleaned before it can be moved outside Zone A

• a permit is required if these conditions are unable to be met. 

The above restrictions do not apply to grass, lawn clippings, leaf like matter or fruits and vegetables as these materials do not host the beetle and 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.