In 2017, the Polyphagous Shot Hole Borer (euwallacea fornicatus) was detected on London Plane trees in the KwaZulu-Natal National Botanical Gardens in Pietermaritzburg. Native to Southeast Asia, this beetle has a symbiotic relationship with the fungus (Fusarium Euwallaceae) which serves as a food source for the adults and their larvae.
The beetles can attack a wide range of living exotic and indigenous trees. In susceptible trees the fungus slowly kills the tree. First, the tree’s vascular system begins to fail, leaves begin to thin on the ends of the branches, eventually turning brown, leading to the branch and eventually the tree dying.