Borer Beetle Plan of Action and Info

You have hopefully been keeping abreast of recent articles in the media and our HGC newsletters about the shot-hole borer.  The Polyphagous Shot Hole Borer (PSHB) is a tiny beetle (barely bigger than a small ant) that has invaded our suburb and looks to threaten the identity of our tree-dense suburb.  This newsletter aims to give you more information about the PSHB, the scale of the problem and the proposed action plan that the HGC together with committed residents, the University of Pretoria and service providers propose to curtail the impact of this unwelcome pest.



Proposed action plan – who is involved?
Recognising the looming threat to our neighbourhood, the HGC and certain ‘tree-loving’ residents have formed a response team to evaluate the extent of the PSHB infestation in Hurlingham; formulate an appropriate response to curtail further infections and save our trees (where possible). 

The trees in our suburb are one of our most valuable assets, making Hurlingham a sought after area.  It would be sad to see that destroyed as a result of inaction by residents and other stakeholders.

The response team (already affectionately known as the ‘Borer Bashers’) met with representatives from three arborist companies currently known to be operating in the area (contact details below) and a professor from the University of Pretoria’s Forestry and Agriculture Biotechnology Institute (‘FABI’) in early April.  FABI has begun to accumulate a wealth of knowledge about the PSHB and is in contact with other institutions around the world who are also studying this beetle. 

As not enough is known about the PSHB and how it has adapted to South Africa (see discussion below), FABI is excited to be working with us to learn more about how the PSHB infestation has adapted in our climatic environment and assist in experimenting on the most effective treatment going forward. 

Johannesburg City Parks have given permission for the study group to conduct a chemical-controlled trial on the pavement trees in our suburb (did you know that City Parks are the ‘owners’ of these trees?).

Proposed action plan – what next?
1) Initial assessment
FABI have volunteered the services of a group of approximately 12 university graduates (Honours, MSc and PhD students) from the University of Pretoria to make an initial assessment of the extent of affected trees in our suburb. 

It is thought that we will identify a designated street for this initial assessment which will involve a detailed inspection of all the trees in residents’ gardens and pavements in that street.  We believe that involving students from FABI will be a cost effective way of conducting the research that is required and possibly finding a solution that can be utilised across the country.  

We anticipate undertaking the initial assessment in early May.  Whilst we have not yet identified the respective ‘street’ that will be subject to the initial assessment, if your home is identified, we implore you to please be as co-operative as possible with the needs of the initial assessment study

We will take the necessary security precautions with respect to people entering your properties (remember at no time do you need to let anyone into your house!) and will be working through the relevant street reps to communicate relevant information.  Please assist us in making your garden open for your trees to be inspected – the initiative aims to benefit not only your trees, but the entire neighbourhood!

It would help a great deal if you are able to identify/name unusual tree species if your garden is selected, as many of the students are not tree experts (mostly microbiologists and entomologists). The FABI staff/students will also ask you to sign a permission form to survey your trees and take samples if needed.

It is hoped that the initial assessment will give us an idea of the extent of the problem and be a potential learning curve for establishing how long a complete assessment of the neighbourhood would take and how best to roll it out to the greater suburb.

We are also planning to send out a short questionnaire to all residents to get an indication of numbers of trees and species in their yards and streets to assist us for planning purposes.

2) Information session and feedback of initial assessment
Following the collation of information from the initial assessment, we expect to be able to hold a ‘borer beetle information session’ later in May.  This session (venue to be advised) will be open to everyone in the community and surrounds.  You don’t need to be a contributor to the HGC to come and learn about the effects of PSHB!

Experts in the field will share more information about the PSHB and the results of the initial assessment.  This will include a presentation on the problem and what is currently known about it in South Africa but also from abroad. We hope to be able to share information about:

  • The species of trees that are infected in our area;
  • Which species are thought to be ‘reproductive hosts’ (see explanation below) and are strongly advised to be destroyed;
  • What you as a homeowner can do to ‘protect’ your trees – if anything;
  • Steps that FABI plans to take with respect to experimental chemical treatments on the trees on our pavement.  Experimental treatments will probably only commence end August/ beginning September as  trees have to be actively growing to absorb the chemicals.; and
  • Further proposed actions and funding requirements thereof.

3) Further action
Depending on the outcome of steps 1) and 2), we hope to extend the assessment to the rest of the suburb with the assistance of FABI students and/ or professional arborists so as to identify an infection ‘heat map’ for the entire suburb.

Once we have more detailed information as to the extent of the problem, we will be better placed to consider the extent of an appropriate plan of action for our suburb.  We expect that we will need to also consideration of how best to fund these plans.

In the interim, if you would like to contact one of the arborists to come and do an assessment of the trees in your garden (highly recommended), please scroll down to find contact details of the arborists that have been active in our area and are ‘on board’ with us in this project.

It is important to note that NOT ALL trees infested with the beetle and fungus will die.  At this point no one is able predict which species will die, especially with regards to native species. This highlights the importance of this project, not only to Hurlingham but to the greater South Africa.  No one wants to cut down or treat trees unnecessarily, but we need to be responsible in cases where infested trees pose a risk to the other trees in the environment, humans or property.
Your assistance and commitment in working with the response team will determine the success and sustainability of the project.  We have some committed individuals on board as well as the support of a top class academic institution (FABI).  We ask for your help in maintain the character of our suburb and making this project work!!

Please contact your street rep if you have any further questions or comments.
Additional information about the PSHB
Which trees are at risk?
Believed to be native to South East Asia (Vietnam), the PSHB has wreaked havoc in California and Israel in especially avo orchards, and there is great concern that it is putting Johannesburg’s tree canopy at risk.  It is not known how the beetle arrived in South Africa, but it has been already been detected in different parts of South Africa across an array of climatic conditions.  Whilst other beetle species will attack only a certain species/ family of trees, the PSHB is ‘unique’ in that it does not seem to ‘favour’ any particular species of tree. 

As many as 50 different tree species have already been infected by the PSHB in South Africa – including some of our indigenous trees.  Whilst other borer beetle species target ‘sickly’ trees or dead wood, the PSHB attacks both healthy and stressed trees.  It does not appear to favour dead wood – probably on account of the fungus needing to replicate in the live sapwood of a tree.

What does the PSHB do?
The flying beetle lands on a host tree and begins boring into the tree trunk, creating a hole of approximately 1mm in diameter.  The beetle carries a fungus which is deposited in the tunnels it creates through its boring activities.  The fungus is often visible on the outside of the tree by the dark ‘ring’ that forms around the tiny hole bored into the bark of tree. The beetle and its larvae feed off fungus that grows inside the tunnels and colonies that it builds within the tree.

It is not the beetle itself, but rather the fungus that will potentially kill the tree.  Once deposited in the tree, the fungus spreads to the sapwood of the tree - impacting on the ability of the tree to distribute water and nutrients to the rest of the tree.  Sections of the tree will start to wilt and ‘die back’ until eventually the entire tree may die.

Once the borer beetle infests a tree it completes its life-cycle deep inside the wood beyond the reach of surface application of pesticide treatments.  Insecticides do not appear to be particularly effective against eradicating the PSHB since the beetle does not ingest the wood.  Pesticide treatments are thought to only be effective if the beetle is burrowing in the outer layer of the tree.

What is known about the PSHB?
Not enough information is known at present about the beetle and how it has adapted to the South African climatic conditions.  We don’t know exactly which species of trees are susceptible to PSHB; how the life cycle has adapted to South African climatic conditions; how many life cycles will be completed in a South African season; or whether the beetle will go dormant in winter.  What we do know is that:

  • As many as 50 different tree species have been infested by PSHB;
  • Not all trees appear to die after having been infested by PSHB.  In some cases, whist having been infested by PSHB the beetle does not seem to breed in the tree;
  • Other tree species (English OakChinese Maples and Box Elders in particular) appear to be reproductive hosts.  Here the beetle will establish large colonies within the tree which become a breeding ground for future infestation of surrounding trees.  In these cases we think it is prudent for the tree to be cut down and destroyed through burning or fumigation to prevent contamination to other trees in the neighbourhood.

What does PSHB infestation look like?
Different trees seem to respond differently to infestation by the PSHB. 

  • Some trees will ooze a resin-like substance from the holes where the beetle has bored into the tree;
  • Other trees will show ‘weeping’ signs from the borer holes where it looks like tree sap has wept out of the tree;
  • In extreme cases you will be able to see the ‘sawdust’ result at the base and in crevices of the tree where the borer has been active;
  • In all cases however you will see the ‘shot-gun like’ holes in the tree where the borer has bored into the trees.  When the bark is peeled away, many of the holes will display a dark ‘ring’ around it which is evidence of the fungus growing in the tree.

For further information and loads of useful photos, log onto

What is City Parks doing?
Relevant stakeholders have been engaging City Parks with respect to the problem – you may have seen City Park’s media statement dated 11 April 2019.  Unfortunately they appear to have been slow off the mark and have only recently formed an in-house strategic committee to consider the problem and report back to the Board. 

The most pressing issue is for them to make a ‘dumping ground’ available where infected wood can be collate and burnt.  There is great concern that we will assist the beetle in spreading if we merely send cut wood to composting sites to be turned into mulch and spread into uninfected gardens!  If you have a tree felling company that is felling infested trees for you – ask them what they are doing with the infected wood!

Who can I contact?
We currently have three specialist arborists who are working with the ‘borer basher’ response team and have been active in our area with respect to, not only PSHB, but tree care in general.  We are confident in the extent to which they are linked into the appropriate knowledge hubs (and to each other) so as to share new information as it becomes available.  Should you wish to contact an arborist to do an assessment of the trees in your garden (HIGHLY ADVISABLE), we suggest you contact them via the contact details below:

  • Urban Forest                        (011)  022 0840
  • Tree Works                           (011) 884 8088
  • Arbor Tree Care                    083 430 2000

A consultation will generally involve an assessment of the trees in your garden; an identification of which trees are infected by PSHB; and a proposal on to how best to proceed (remove the tree or try and treat it).

Please be aware that to date, no chemical solution/ treatment/ spray etc. has been found to be 100% effective in treating PSHB.  All treatments are experimental as not enough is known about the species of trees that are ‘saveable’ or which treatments are most effective.  Be wary of anyone who tries to sell you a ‘golden bullet’ with a guarantee that they can save your beautiful and established trees!
More information on the beetle can be found at:


Important Contacts

HGC Committee:
Flying Squad: 10 111
Randburg SAPS vehicles: 071 675 7115 / 6
Ambulance: City: 011 375 5911
ER24: 084 124
Netcare 911: 082 911
Randburg Police: 011 449 9115 / 9110 / 9117 10111 for an emergency
Joburg Metro Police: ​011 375 5911
Joburg call centre: 0860-JOBURG
Includes City Parks and Pikitup
See Community Info --> Overview section for a full list of numbers
Water Issues: Joburg Water

011 375 5555
Electricity Issues: http://​ ​and click "Fault Reporting" or on mobile
Road Issues: ​
Environmental Contraventions: 011 587 4232 1st point of contact for any issues arising from the Health Act (noise, restaurants, unsanitary backyards etc)
Pollution: 011 226 8328
Revenue Queries: ​011 375 5555
Traffic Signs and Markings: Jurie Swart JRA - Assistant Manager, Traffic Signs and Markings section for Region B
Region B Contacts and Information:
Building regulations: 011 407 6111
Eskom: 086 003 7566