The City of Cape Town wants to inform residents that a tree infested with the invasive Polyphagous Shot Hole Borer beetle (PSHB) was discovered on a private property in Newlands yesterday afternoon, 24 January 2023. The City is currently on site, advising the resident on the safe removal of the tree as prescribed by the City’s protocol to prevent the spread of this damaging beetle.
The infested tree is a Boxelder, and is situated on private property in Kildare Road, Newlands. Surrounding property owners are advised to inspect trees on their properties as a matter of urgency.
A PSHB beetle infestation was first discovered in Oldenland Road, Somerset West, in an ailing London plane in March 2019. To date, only trees in the Somerset West area have been affected and removed.
‘We are extremely concerned about this latest sighting in Newlands as to date we have managed to contain the invasive Asian borer beetle to the Somerset West area with the assistance and cooperation of residents.
‘Officials from the City’s Invasive Species Unit are currently on site to assess the situation to determine the extent of the infestation and the number of affected trees. The City is assisting the owner with the handling of the biomass. The wood from the tree must be chipped on site, and carefully removed under cover of heavy duty plastic and incinerated at an appropriate site,’ said the City’s Deputy Mayor and Mayoral Committee Member for Spatial Planning and Environment, Alderman Eddie Andrews.
The City will only know how many trees have been infested once the assessment has been concluded. For now, we can confirm that at least one Boxelder is impacted.
‘I encourage residents in the Newlands area to please inspect the trees on their properties for possible beetle infestations, in particular Boxelders. Sightings must be reported to the City as soon as possible so that we can prevent the spreading. More information is available on the City’s website, as well as a form to report sightings. By working together we can contain this beetle,’ said Alderman Andrews.
How to report PSHB beetle sightings
Information about the borer beetle is available on the City’s website; included are photos of infected trees and what symptoms to look out for.
Use the following link: https://www.capetown.gov.za/City-Connect/Activities-and-programmes/Nature-and-environment/invasive-species-programme, click on ‘Invasive Tree Bug Awareness Notice’ for more information.
There is also a link to report a sighting to the City. Just give your details and the location of the infected tree and officials from the City’s Invasive Species Unit will conduct an investigation.
More about the PSHB beetle
The beetle is the size of a sesame seed, approximately 2 mm in length, and its symbiont fungal partner are threatened trees across South Africa
It is an ambrosia beetle native to Southeast Asia
It was first discovered in South Africa in 2017 on London plane trees in KwaZulu-Natal’s National Botanical Gardens in Pietermaritzburg
The beetle is invading and poses a threat to exotic and indigenous trees across South Africa
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
Lifecycle of the PSHB beetle
The female beetle carries with her three species of fungi, including the pathogen, Fusarium euwallaceae
The adult females burrow into trees to establish brood galleries where they lay their eggs. They introduce the fungus which colonises gallery walls, becoming a food source for developing larvae and adult beetles. The fungus kills the water conducting tissues of the tree and can lead to branch dieback and eventually causes the tree to die
The following trees are invaded
Alien trees infested to date include London plane trees, Liquidamber, Japanese maples, Chinese maples, pin oaks, and English oaks
Indigenous trees invaded to date include the Coast Coral tree, Forest Bushwillow, and the Cape willow
What to do
Burning of the infected wood is the preferred method
Chipping of the wood into small pieces for compost is also recommended as the heat build-up in the composting process will kill the beetle
Once the tree has been felled the debris should be cleared as soon as possible and if required, the area should be sanitised
Infested plant material can be placed in refuse bags and sealed. The bags must be put in direct sunlight for solarisation as the heat from the sun helps to kill the beetle and its larvae
Best practice protocol
The City of Cape Town’s Invasive Species Unit, in cooperation with the City’s Recreation and Parks Department, local arborists and the country’s top entomologists, developed a PSHB protocol which prescribes the best practice for how to remove and dispose of trees infested with PSHB.
The Polyphagous Shot Hole Borer Protocol is useful for identifying, pruning, cutting down, removing and disposing of infected PSHB wood.
Experiences in California, Israel, and closer to home – in Gauteng, have shown that the PSHB beetle can easily spread across suburbs if extra precaution is not taken. Apart from infected wood, the 2 mm big borer beetle can also spread through clothing, vehicle crevices, or unclean horticultural equipment.
The movement of infested wood is an important pathway for the spread of the beetle. Appropriate disposal of infested trees – by chipping and then incineration, solarisation, or composting – is therefore essential for reducing the spread of the pest.
The use of pesticides and fungicides have a limited effect. These may reduce the rate of recolonisation in lightly infected trees, but have not proven effective at eradicating PSHB from infected trees.
Source: City Of Cape Town