Pest Potential
EHB has been very destructive in countries where the pest is established.
Following discovery of EHB in 2004, climate modelling showed that all of southern Western Australia was at risk, south of a line from Carnarvon to Ceduna. Without action, it was estimated the borer would spread to infest this entire area by 2040.
Subsequent research confirmed that EHB eggs, larvae and beetles could survive in Perth's high summer roof temperatures. As of September 2010, there has been one confirmed structural find of EHB in a home, that was the result of EHB migrating from nearby infested pine trees.
The main threat is to homes located close to infested pine trees, as research has shown that adult beetles can fly up to 1-2km in search of host material. While an adult beetle will usually only travel after its food source has been exhausted (which could take 10-20 years), some long distance travel has been evident.
DNA testing shows that original EHB populations may have migrated from the hills region to Gnangara, which could have resulted from EHB beetles being carried on prevailing easterly and south-easterly winds in Perth summers. The presence of infested pine tree host bridges between two areas may also result in migration.
Additionally, EHB have been known to 'hitch-hike' on vehicles transporting untreated pinewood during the flight season, which poses a threat even to homes not close to infested areas.
The good news is that EHB has a long lifecycle of 2-5 years (12 at the most), which is believed to be insufficient time for the borer to cause structural damage. Significant EHB damage will usually occur when an adult beetle lays eggs in the piece of timber from which it emerged, resulting in 2-3 generations of destructive tunnelling.
In South Africa, it took 20-25 years of EHB infestation for structural collapse to occur. If EHB can be detected in its first generation of infestation, this situation can be avoided in Western Australia.
The EHB Response has developed a number of management strategies to ensure infestation is discovered early, and that spread and damage is minimised. Although, the effectiveness of these strategies will depend on support from industry, relevant government agencies and communities.
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