Research Features
The Polyphagous Shot Hole Borer is an ambrosia beetle native to Southeast Asia. In 2017 this pest was detected in South Africa. Its presence has since been confirmed in all provinces except Limpopo. The beetle has a symbiotic relationship with the fungus Fusarium euwallaceae, which causes branch die-back and death of susceptible trees.
The Polyphagous Shot Hole Borer (PSHB) and its fungus in South Africa
FABI information pamphlets on the PSHB
PSHB - Information sheet PSHB - Life stages of the beetle PSHB - Symptoms
PSHB - External symptom types PSHB - How to photograph for diagnosis PSHB - How to sample
Californian information pamphlets - Californian host tree list
Background
As a participant in the International Plant Sentinel Network (IPSN), Dr Trudy Paap had been tasked to conduct surveys for tree pests and diseases in South Africa's Botanical Gardens, a project funded by the South Arican Biodiversity Institute (SANBI). It was during such a survey that she noticed small lesions resembling shotgun marks on the stems and branches of mature London plane trees (Platanus x acerifolia) in the historical avenue of the KwaZulu-Natal National Botanical Gardens, Pietermaritzburg. Upon closer inspection, she found that the lesions developed around entrance holes of small beetles. When she removed the bark, the sapwood was discoloured by a fungus. She brought samples back to FABI, and with the assistance of FABI team members, the beetle and fungus were identified based on DNA sequences as Euwallacea fornicatus (Polyphagous Shot Hole Borer or PSHB) and Fusarium euwallaceae, respectively. The results were published in the Australasian Journal of Plant Pathology (Paap et al. 2018).
Click here to read more about Euwallacea fornicatus (Polyphagous Shot Hole Borer or PSHB) and Fusarium euwallaceae on Research Matters to find out how this is affecting South Africa’s forests.
Click here to read more about how Fusarium euwallaceae kills trees on Research Matters and what FABI researchers are doing about it to try to curb the spread.
The Polyphagous Shot Hole Borer can have a potential cost for commercial farmers as well, which is explained further with a short video which explains what we can do to help our trees against this damaging invasive pest.
