How to Identify

How do you know if your tree is infected? The name says it all: The Shot Hole Borer burrows into different trees in burrows smaller than a ballpoint pen tip.

Your tree will not die quickly or easily. As the tiny PSHB beetle lives inside the wood it is unlikely to be noticed crawling on the bark.

Depending on the tree, identification differs. Sings of infestation could be sawdust collecting on the bark and around the base of the tree, in other trees there may be an oozing of liquid and gum from the beetle holes.

Here’s a closer look at the PSHB, and how you can spot infestation.

21 tree species have been identified as “Reproductive Hosts” within South Africa and evidence of PSHB has been found in 151 trees species within South Africa.

Host trees can be defined as either Reproductive Host Trees or Non-Reproductive Host Trees. Reproductive host trees are trees where the PSHB can successfully reproduce, and which eventually die due to the fungus. Non-Reproductive host trees are attacked by the beetle, but PSHB reproduction is not successful. The fungus might or might not disease and eventually kill these trees.

Australian Blackwood (Acacia melanoxylon)
Avocado (Persea americana)
Black wattle (Acacia mearnsii)
Boxelder (Acer negundo)
Castor bean (Ricinus communis)
Chinese maple (Acer buergerianum)
English Oak (Quercus robur)
Honey locust (Gleditsia triacanthos)
Japanese maple (Acer palmatum)
Liquidambar; American sweetgum (Liquidambar styraciflua)
London Plane (Platanus x acerifolia)
Pin oak (Quercus palustris)
Pink flame (Brachychiton discolor)
Southern magnolia (Magnolia grandiflora)

Fever (Acacia zanthophloea)
Flat crown (Albizia adianthifolia)
Coast coral (Erythrina caffra)
Common coral (Erythrina lysistemon)
Natal fig (Ficus natalensis)
Wild plum (Harpephyllum caffrum)
Pigeonwood (Trema orientalis)
Paper bark thorn (Vachellia sieberiana var. woodi)
Wild frangipani (Voacanga thouarsii)

The Tree Survey mobile app allows you to report infestations. Each reported incident receives in-app feedback. You can just report the bug, or you can select a further action from either a City Parks official or a private service provider.

To illustrate the impact of the of the borer, South African arborists explored the nature of the borer’s tunnel and to determine the impact of the fungus on the trees vascular system.

Here is an inside peek into how the PSHB enters a tree:

How to Identify

IS MY TREE INFECTED?

WHICH TREES ARE AFFECTED?

REPRODUCTIVE HOST – Exotic Trees

REPRODUCTIVE HOST – Indigenous Trees

TREE GENUS EXAMPlES

Species – London Plane