Preschem has discussed borer treatments and their life cycle in this news post on the website. Unfortunately, once you have noticed the pin holes and dust/fras, the adult beetle has emerged from the wood and done its damage. But here are the things you can do to try and prevent further damage.
- Photograph the holes to assist you in identifying new borer activity
- Treat the timber with either Clear Wood Preservative or No-Rot Gel
- Monitor the timber for signs of new holes for 2-3 months afterwoods and retreat if necessary
To figure out which product is suitable for your situation, then:
- If the timber is sealed with a varnish or paint or is external and exposed to the weather, use Clear Wood Preservative. Note: Clear Wood Preservative can be flooded into the pin holes with a small needless syringe, It can even blown in with a hear dryer (use the fan only, no heat)
- If the timber is raw and internal, use No-Rot Gel