Tree Alert – PSHB

A tiny beetle poses a huge threat to trees in South Africa

This article by Ida Wilson and Hilton Fryer requires an active response after reading it. Please follow the action steps listed at the end.

A minute exotic beetle that carries disease-causing fungi is threatening tree life in South Africa. This beetle bores holes into mostly the trunks of healthy, living trees where it cultivates a fungal garden to feed on. The beetle itself is small, and it does not feed on the host tree, but it rather feeds on the fungi that it cultivates in the tunnels it bores throughout the tree. Therefore, the beetle on its own holds little threat to the trees. The fungi, however, are tree disease-causing organisms (mostly belonging to the genus Fusarium) and a wide range of trees will become ill and may die when infected with these fungi.

The beetle-fungus pair was formally recorded for the first time in KwaZulu Natal in South Africa in 2017, but it is likely to have been here for a while before the first formal record. During the past few years that it has been present in South Africa, it has caused significant damage – mostly to thousands of urban trees that died in Johannesburg, but also to numerous other tree hosts spread widely throughout the whole of South Africa.

Read the full article here:  PSHB IW HF Final 26 June

Major threat to all trees in South Africa

London plane tree

Residents of the Cape Town’s Helderberg area are requested to NOT prune, remove or cut down any London plane trees, oaks or liquidambers suspected of being infested by the invasive Polyphagous Shot Hole Borer (PSHB).

All trees suspected of being infested with PSHB MUST be reported to the City of Cape Town Invasive Species Unit and inspected before any action is taken.

Experience in Gauteng – where the PSHB infestation has been established for over two years – has shown that it is extremely important to dispose of infected wood by trained teams, who are following established removal protocols.

It is estimated that there are usually well over 100 000 PSHB beetles in a tree that has a single branch exhibiting signs of fusarium dieback.

Getting a private tree feller to cut down a tree and transport it on the back of a bakkie … will allow thousands of PSHB beetles to fly off the tree … as the dead wood is moved to a dump.

The City of Cape Town Invasive Species Teams are trained in vector pathways and how to clean equipment. They also know how to safely chip trees on site and remove the infected wood – under plastic – to designated sites for burning or solarisation.

HOW TO REPORT PSHB

The ISU has been inundated with requests for identification assistance and is unable to deal with reports coming in over the telephone.

Please assist the ISU by reporting your suspected PSBH invasion with a full dossier of images and information submitted via the website reporting tool: 
https://www.capetowninvasives.org.za/shot-hole-borer