Invasive tree-killing beetle found in Constantia

An invasive tree-killing beetle has spread to Constantia, says the City.

The City’s Invasive Species Unit confirmed a boxelder infected with the polyphagous shot hole borer beetle was discovered in Alphen on Thursday April 18.

Surveys are being done to confirm how many trees in the area have been infested, says mayoral committee member for spatial planning and environment Eddie Andrews. He asked residents to give Invasive Species Unit monitors access to their properties.

“I am urging all private landowners in Alphen and Constantia to please inspect the trees on their properties for symptoms and to contact us immediately should any of these be visible on any trees,” he said.

“We are extremely concerned about the latest sighting and request the assistance and cooperation of residents and businesses that work with plant material.”

All City staff will be identifiable in City of Cape Town branded clothing and will present official staff identification cards to gain access to properties.

According to the City’s latest infestation statistics, 24 trees have been infested in Penhill, Eerste River; 309 sightings of infested trees have been recorded in Newlands, Rondebosch, Mowbray, Claremont, Kenilworth, and Observatory along the Liesbeek River; and over 4 975 infested trees have been sighted in the Helderberg area since 2019.

The beetle poses a serious threat to Cape Town's urban forest as infested trees have to be chipped. And pesticides and fungicides have not proven effective at eradicating the pest.

The City warns that the 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.

What to look out for and symptoms of infested trees:

• Branch die-back – 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.

Infested trees 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 firewood from areas where trees are infested.

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 at appropriate incineration facilities.

• Seek assistance from trained and equipped service providers with sound knowledge of the beetle.

• Do not move plant or tree material, including firewood, outside of beetle-infested areas.

• Do not transport any form of green waste in open vehicles.

• Clean tools and equipment used to prune plants.

To report beetle sightings, contact the City’s Invasive Species Unit at 021 444 2357 or invasive.species@capetown.gov.za

According to the City, the response to verify a reported sighting can take up to 10 working days, depending on the number of sightings reported.