Shot hole borer on the march through Cape Town trees, city council warns

15 May 2019 - 09:43 By TimesLIVE
The first example of a polyphagous shot hole borer in an English oak in Somerset West.
The first example of a polyphagous shot hole borer in an English oak in Somerset West.
Image: City of Cape Town

Authorities in Cape Town are bracing themselves for the spread of tree-killing beetles.

The polyphagous shot hole borer has been found in trees in the Somerset West suburbs of Helderrant, La Sandra and Worlds View in Somerset West, the city council said on Wednesday.

“The city anticipates that more locations will be reported as public awareness increases and trees on properties and streets within the vicinity of the initial sighting are inspected,” said a statement.

Cape Town council staff chip a tree infested with shot hole borer in Helderrand, Somerset West.
Cape Town council staff chip a tree infested with shot hole borer in Helderrand, Somerset West.
Image: City of Cape Town

Shot hole borers dig tunnels into numerous tree species to lay eggs They have killed thousands of trees countrywide by depositing fungus that block the tree's internal transport system.

“The shot hole borer attacks a variety of tree species which include maples, oak, avocado and plane trees. Some acacias, willows, and indigenous trees can also be affected,” the city council said.

“These species include some of the most common and valuable trees in Cape Town, and the threat posed to the indigenous species is a serious risk to ecosystems.”

A hole made by a shot hole borer in a tree in Somerset West.
A hole made by a shot hole borer in a tree in Somerset West.
Image: City of Cape Town
Stained bark is a symptom of shot hole borer infestation.
Stained bark is a symptom of shot hole borer infestation.
Image: City of Cape Town

The most common symptoms of infected trees are gum or sap oozing on the bark, entry and exit holes, sugary deposits, sawdust, staining on sapwood and bark, and dieback.

“There is no fully effective or registered treatment for either the insect or the fungus. Severely infested trees are removed and destroyed in order to contain the spread of the disease,” said the council.

“Special care has to be taken throughout the entire removal process. Minor infestations on some species which are non-reproductive hosts may be monitored or treated.”

The mayoral committee member for community services, Zahid Badroodien, said members of the public should not cut down infested trees or dump them, as this may spread the fungus.

“The city’s recreation and parks department is the custodian of thousands of trees in our parks and public spaces, and we are concerned about the potential impact of the beetle on these valuable assets,” he said.

“Our staff are keeping a close watch on these spaces, but we need the public’s assistance.”

Sightings of the shot hole borer can be reported on the municipality's website or on
0860 103 089. The exact location of the sighting is important.


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