The Polyphagous Shot Hole Borer: A Growing Threat to South Africa's Trees

Recently we had the privilege of hosting a speaker, Paul Barker, who works closely with identifying and eradicating the Polyphagous Shot Hole Borer

The Polyphagous Shot Hole Borer (PSHB) is an invasive beetle native to Southeast Asia that has seriously threatened South Africa's trees. The first detection was in 2017 on London Plane trees in the KwaZulu-Natal National Botanical Gardens in Pietermaritzburg. The PSHB has since spread to multiple locations across eight provinces.

This tiny beetle, about the size of a sesame seed, may seem insignificant, but it carries with it a deadly companion: the fungus Fusarium euwallaceae. The beetle has a symbiotic relationship with this fungus, which it uses as a food source for itself and its larvae. Unfortunately, this fungus is also a tree killer. In susceptible trees, it causes a disease known as Fusarium dieback, which leads to dying branches and, ultimately, tree death.

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