Borer beetle pest sighted in Durbanville
21 January 2025
The City of Cape Town wants to inform residents that samples taken from a Boxelder and Sweet Viburnum tree on a private property in Durbanville tested positive for the invasive Polyphagous Shot Hole Borer beetle (PSHB). This latest infestation is the first to be discovered in this area, and is of great concern. Read more below:
The City was first notified of a possible infested tree in Durbanville and deployed a team of monitors from the Invasive Species Unit to assess the area and to collect samples for DNA verification. Following the DNA verification, unfortunately it has been confirmed that the Boxelder and Sweet Viburnum trees are indeed infested with PSHB.
Several other trees including English Oak, Liquid Amber and Chinese Cottonwood on the same property and the neighbouring property have also been found to have PSHB symptoms.
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‘At this point, we cannot confirm the number of infested trees in the Durbanville area as a whole as surveys are currently under way. I am urging all private land owners in Durbanville to urgently inspect the trees on their properties for symptoms and to contact us immediately should any of these be visible on any trees. The City also needs access to private properties to conduct a full assessment to determine the extent of the infestation in and around Durbanville. I therefore ask residents please to give the teams access to their properties so that we can determine the extent of the PSHB infestation. We are extremely concerned about the latest sighting and request the assistance and cooperation of residents and businesses that work with plant material,’ said the City’s Deputy Mayor and Mayoral Committee Member for Spatial Planning and Environment, Alderman Eddie Andrews.
The City will communicate information on an important community training session for Durbanville residents once details have been confirmed.
Boxelder trees for example are one of the four highly susceptible reproductive host trees for PSHB. Both the beetles and the fungus are able to establish, and the beetle successfully reproduces in these trees. Once attacked, Boxelder trees typically die within one year and they amplify the PSHB population and increase the risk to surrounding trees. Boxelder is thus an ideal tree that can be used as an indicator of an early infestation in a new area. All landowners across the City with Boxelder trees on their properties are to please notify us by logging these trees on https://www.inaturalist.org/projects/box-elders-cpt. This will help the City set up monitoring interventions that will assist with catching a new invasion early.
All staff doing the survey and tree assessments will wear City of Cape Town branded clothing and will present official staff identification cards to gain access to properties.
Latest infestation statistics (excluding Durbanville):
•To date, 26 trees have been infested in Penhill, Eerste River, among which Boxelders, London Planes, English Oaks, Beef Wood, Weeping Willow, Cape Chestnut, Black Locust, Paperbark and Maples
•Over 400 sightings of infested trees have been recorded in Newlands, Rondebosch, Mowbray, Claremont, Kenilworth, and Observatory along the Liesbeek River
•Over 5 700 infested trees have been sighted in the Helderberg Area since 2019 to date
What to look out for and symptoms of infested trees:
• Branch dieback – cracks on the branch; discoloured leaves; dry and leafless branches; branch break-off revealing webs of galleries filled with black fungus
• Gumming – blobs of goo coming out of the bark; oozing of liquid and gum from the beetle holes
• Entry and exit holes – very small holes on the bark of the tree, the size of a sesame seed (2mm); shotgun-like scars developing around the holes
• Staining – brown or dark stains on the bark of the tree
Important: infested trees must be chipped on site and may not be removed from the property as the removal of the chipped wood will spread the pest to other areas. Do not buy and move fire wood from areas where trees are infested.
How to report PSHB beetle sightings:
• Online, at www.capetown.gov.za/InvasiveSpecies
• Call the City of Cape Town’s Invasive Species Unit on 021 444 2357, Monday to Friday, from 07:30 to 16:00
• Send an email to: invasive.species@capetown.gov.za
What to do:
• Chip the tree, place the infested material in refuse bags, seal it and put these in direct sunlight for at least six weeks
• Dump the chips in your compost heap as the heat build-up will kill the beetle
• Burn infected wood chips at an appropriate incineration facility
• Where chipping is not possible, cut infested wood into smaller pieces that can fit into solarisation plastic bags
• Tightly close and seal the bag with infested material and place it in an area with direct sunlight and leave it to solarise for at least six weeks in summer and up to six months in winter
• Seek assistance from trained and equipped service providers with sound knowledge of PSHB
• Do not move plant/tree material/firewood from areas where PSHB has been confirmed to be present to other areas
• Do not transport any form of green waste in open vehicles, cover it with sail covers even if no PSHB has been identified as such green waste.
• Clean tools and equipment used to trim/cut/prune plants
Importantly, the use of pesticides and fungicides have not proven effective at eradicating PSHB from infected trees. The PSHB beetle can easily spread across suburbs if extra precaution is not taken. Apart from infected wood, the beetle can also spread through clothing, vehicle crevices, or unclean horticultural equipment.
The PSHB poses a serious threat to Cape Town's urban forest as infested trees have to be chipped.
The City will try its best to respond within 10 working days to verify a reported sighting. However, the response time will depend on the number of sightings reported.
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Issued by: Media Office, City of Cape Town
Published by:
City of Cape Town, Media Office
