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Persistent Borers in Pittosporum: Consult an Entomologist

When trunk-applied insecticides (e.g., Rogor) fail to control borers in pittosporum after three months, the issue may be timing, product choice, or borer species resistant to that chemistry. Most borer insecticides work best as preventives applied before egg hatch.

Recommended Approach

Contact a certified entomologist or your state Extension specialist for species-specific advice.
Systemic neonicotinoids (imidacloprid, dinotefuran) applied as soil drenches often outperform contact sprays.
Remove and destroy heavily infested branches to reduce population.
Maintain plant health to tolerate low-level infestation.

Borers deep in wood are difficult to reach; professional guidance is worthwhile for valuable plants.

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