Do I have borers in my Lime tree?

[ColinCHB]

The tree is about 2 years old and seems quite healthy - but recently has this spag-moss/wood shavings substance on its trunk.

I can't see any holes.

I have been told that it could be Collar Rot - but I'm not convinced.

Any ideas?

[EricL]

Hello @ColinCHB 

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

The substance on your tree’s trunk looks like frass, a sawdust-like material often caused by wood-boring insects such as beetle larvae or caterpillars. While you mentioned there are no visible holes, this type of debris is a clear indicator of pest activity inside the tree, even if the entry points are tiny or hidden. Collar rot typically causes bark decay and oozing rather than sawdust-like buildup, so it’s less likely in this case.

Start by closely inspecting the trunk for small entry holes, cracks, or any sap oozing from the bark. Sometimes, insect damage can be subtle, but brushing away the frass will help reveal any concealed signs. If you confirm pests, consider using a product like Yates Nature’s Way Citrus & Ornamental Spray or Eco-Neem, both available at Bunnings, which are effective for targeting pest larvae and beetles without harming the tree. If pests persist, applying Yates Pest Oil can help smother insects or eggs on the bark.

After treatment, monitor the tree’s health carefully for signs of wilting, yellowing leaves, or further buildup of frass. Maintain consistent watering without overwatering, as pests and fungi thrive in overly damp conditions. If no pests are found and the tree remains healthy, it could simply be minor environmental stress, but addressing the issue early will ensure the tree continues to thrive.

If you need further assistance, please let us know.

Eric

[ColinCHB]

Thanks Eric - appreciate your considered reply - and it aligns with what I thought may have been the case - rather than collar rot.

I will try the products that you have mentioned.

Is there an injectable insecticide that might be considered?

[EricL]

Hi @ColinCHB 

There are currently no injectable insecticides for borers. 

Eric