Information on how to identify possible Polyphagous Shot Hole Borer beetle (PSHB) infestations, where to report it and how to handle the chipped biomass will be shared during an online meeting tonight (Tuesday 7 February).
Until recently confined to the Garden Route and Somerset West in the Western Cape, the invasive beetle that aggressively kills trees was discovered on a private property in Newlands on Tuesday 24 January.
In the past two weeks, the City of Cape Town’s Invasive Species Unit has been conducting assessments in the Newlands, Rondebosch, Mowbray and Claremont areas. Last week, the City stated that the Liesbeek had been identified as a priority pathway.
“The City has allocated resources to conduct assessments to determine the extent and distribution of the beetle in the area,” the statement read, adding that the City would soon commence with the removal of infested trees on City-owned land (public open spaces, river corridors, green belts, road verges, and public parks).
WATCH | Tree-killing beetles spread to Cape Town’s lush southern suburbs
When it comes to monitoring and addressing the spread of the beetle on private land, however, residents’ assistance is required. The City’s by-law states that the tree subsides to the land, which means whoever owns the land, owns the tree and all of its by-products.
Eddie Andrews, the City of Cape Town’s Deputy Mayor and Mayco member for spatial planning and environment, last week called on residents, interest groups and experts to assist the City in preventing this pest from spreading even further.
“The beetle is threatening our urban forest. This is a very serious and alarming situation. I want to caution our communities not to be complacent and to inspect all trees on private properties for symptoms of infestation.”
The beetle’s most likely pathway or vector is through the movement of infested wood, originating from dead or dying PSHB infested trees, including wood intended to be used for cooking or heating.
With the use of pesticides and fungicides thus far only showing a very limited effect, experts state that the only way to prevent the spread of the invasive beetle is to chip affected trees on the property where it has been found and to carefully remove the biomass under cover of heavy-duty plastic.
The contaminated biomass then needs to be incinerated at an appropriate site.
Information on how to handle the biomass will be shared during tonight’s online meeting.
“It is important to note that infested trees may not be removed from the property as the removal of the chipped wood will spread the pest to other areas. I urge residents to please attend this online meeting if possible, and to help us beat the beetle,” says Andrews.
In the meantime, arborist Francois Krige advises residents to identify Boxelders on their property – and to remove them.
“The infestation in the southern suburbs of Cape Town cannot be stopped or contained; there are no licensed treatments for PSHB nor any peer reviewed studies showing that any treatment is effective. The disease can, however, be slowed.”
Krige explains that, by a huge margin, Boxelders (Acer negundo)is an amplifier of this disease.
“The beetle prefers it to any other species. By removing this species from your property you are removing the most potent lure from your property. I would advise this as the most effective step you can take at this point to protect your other trees and your community’s trees.”
Krige also implores residents not to move firewood or plant material out of the southern suburbs.
“Unless you are sure that it is not from an affected species, eucalyptus (gum) is safe. Google Fabi (The Forestry and Agricultural Biotechnology Institute) PSHB for a list of reproductive host species,” he says.
Residents are also being asked for their assistance in identifying and mapping the location of Boxelder trees in and around the southern suburbs using the iNaturalist app. Data collected will be used to help predict the invasion pathway of PSHB.
- The City of Cape Town will host the online meeting on Microsoft Teams from 18:30 to 20:00 tonight. RSVP: https://forms.gle/T7mUexES6Qi9sHnd9
- To join the meeting, click here.
