Shot hole borer risk from mulch?

[Vajrayogini108]

Are bags of mulch sold at Bunnings at risk of being contaminated by polyphagous shot hole borer?

[EricL]

Hello @Vajrayogini108 

Welcome to the Bunnings Workshop community. It's sensational to have you join us, and thanks for sharing your question about mulch.

Bunnings sources its mulch from commercial suppliers who are required to comply with biosecurity regulations. These suppliers process mulch to standards that reduce the risk of pest contamination. For example, in Western Australia, mulch provided by the Western Metropolitan Regional Council is processed to a size less than 2.5 cm, which is effective in killing PSHB larvae.

While specific processing standards may vary by region, the risk of purchasing PSHB-contaminated mulch from Bunnings in Brisbane is currently minimal. 

Keep in mind that an ounce of prevention is worth a pound of cure. Always be vigilant and inspect your mulch before you apply it. Look for signs of infestation, such as small exit holes or sawdust-like frass. If it looks suspicious do not use it in your garden.  

If you have any other questions we can help with, please let us know.

Eric