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Updated on 11 July 2023

Polyphagous Shot-Hole Borer (PSHB)

The polyphagous shot-hole borer beetle (PSHB), Euwallacea fornicatus, is an invasive ambrosia beetle native to Southeast Asia, which has caused significant damage to a wide variety of trees in urban, suburban, natural landscapes, and on farms.

Beetles In Gallery John Kabashima Web
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Close Up Of Millenial Platanus In Autumn With Fallen Leaves

PSHB was first discovered in 2017, in the KwaZulu- Natal Province infesting plane trees. The beetle has spread across South Africa and has infested more than 140 tree species.

The beetle bores into healthy trees, usually branches >35mm, trunks and stems, making round, small holes of ┬▒1mm.

PSHB has a symbiotic relationship with the fungus Fusarium euwallaceae, which the beetle carries in special internal structures and propagates when starting a new tunnel system.  The beetle farms the fungus inside the tree as a food source for itself and its larvae. Actions by the fungus-beetle complex ultimately disrupt the flow of nutrients and water that leads to Fusarium dieback and death of highly susceptible host trees.

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