Polyphagous Shot Hole Borer


JOHANNESBURG URBAN FOREST ALLIANCE

The Shot Hole Borer Beetle is destroying our Urban Forest

The polyphagous shot hole borer (pshb) is a type of amborsia beetle that is currently infesting over 200 tree species around the country.

This tiny beetle, the size of a sesame seed does not itself kill the tree, rather
it is the fungus that accompanies the beetle and grows in the borer tunnel.

This fungus impacts the trees vascular system and inhibits the flow of water and nutrients within the tree.

How to identify symptoms:

As the beetle is so tiny it is often not seen, therefore it is better to look for signs of infestation. Symptoms vary from species to species.

JOHANNESBURG URBAN FOREST ALLIANCE

JOHANNESBURG URBAN FOREST ALLIANCE

REPRODUCTIVE HOST TREES1

Exotic species

Native SA species

Latin name

Common name

Latin name

Common name

Acacia melanoxylon

Blackwood

Combretum krausii

Forest bushwillow

Acacia mearnsii

Black wattle

Erythrina caffra

Coast coral tree

Acer buergerianum

Trident (Chinese) maple

Podalyria calyptrata

Water blossom pea

Acer negundo

Boxelder

Psoralea pinata

Fountain bush

Acer palmatum

Japanese maple

Salix mucronata

Cape willow

Brachychiton discolor

Pink flame tree

Gleditsia triacanthos

Honey locust

Liquidambar styraciflua

American sweetgum

Magnolia grandiflora

Southern magnolia

Pearsea americana

Avocado

Platanus x acerifolia

London Plane

Quercus palustris

Pin oak

Quercus robur

English Oak

Ricinus communis

Castor bean

Salix alba

White willow

NON-REPRODUCTIVE HOST TREES2

Exotic species

Native SA species

Latin name

Common name

Latin name

Common name

Bauhinia purpurea

Butterfly orchid tree

Bauhinia galpinii

Pride of De Kaap

Betula pendula

Silver birch

Buddleja saligna

False olive

Camellia japonica

Common camellia

Calodendrum capense

Cape chestnut

Carya illinoinensis

Pecan nut

Calpurnia aurea

Geelkeurboom

Ceiba pentandra

Kapok

Combretum erythrophyllum

River bushwillow

Cinnamomum camphora

Camphor

Cordia caffra

Septee tree

Citrus limon

Lemon

Cussonia spicata

Cabbage tree/ Kiepersol

Citrus sinensis

Orange

Diospyros dichrophylla

Star apple

Eriobotrya japonicum

Loquat

Diospyros lycidioides

Monkey plum

Erythrina livingstoniana

Aloe coral tree

Ekebergia capensis

Cape ash

Eucalyptus camaldulensis

River red gum

Erythrina lysistemon

Common coral tree

Ficus carica

Common fig

Ficus natalensis

Natal fig

Fraxinus excelsior

European ash

Grewia occidentalis

Cross berry

Jacaranda mimosifolia

Jacaranda

Gymnosporia buxifolia

Spike thorn

Melia azedarach

Syringa

Halleria lucida

Tree fuschia

Morus sp.

Mulberry

Harpephyllum caffrum

Wild plum

Platanus occidentalis

American plane

Melianthus major

Honey flower/ Kruidjie-roer-my-nie

Platanus racemosa

Californian plane

Nuxia floribunda

Forest elder

Plumeria rubra

Frangipani

Olea europea subsp. africana

Wild olive

Populus nigra

Lombardy poplar

Podocarpus falcatus

Outeniqua yellowwood

Prunus nigra

Black plum

Podocarpus henkelii

Henkel’s yellowwood

Prunus persica

Peach

Protea mundii

Forest sugar bush

Psidium guajava

Guava

Rapanea melanophloeos

Cape beech

Schinus molle

Pepper tree

Schotia brachypetala

Weeping boerbean/ Huilboerboon

Taxodium distichum

Swamp cypress

Prunus africana

Red stinkwood

Ulmus minor = procera

English elm

Senegalia (Acacia) galpinii

Monkey-thorn

Ulmus parvifolia

Chinese elm

Vachellia (Acacia) karroo

Sweet thorn

Viburnum sinensis

Viburnum

Vachellia (Acacia) sieberiana var. woodii

Paper bark thorn

Vitis vinifera

Grapevine

Virgilia divaricata

Keurboom


1 Host trees in which both the beetles and the fungus establish, and where the beetle successfully reproduce. In most cases the reproductive hosts will eventually be killed by the fungus.

2 Host trees that are attacked by the beetle and where the fungus establishes, but where the beetle does not successfully breed. The fungus might, or might not cause disease and kill the trees.

JOHANNESBURG URBAN FOREST ALLIANCE

Watch the video below:

In South Africa, some Evergreens are also affected




PSHB Image Unavailable PSHB Image Unavailable
PSHB Image Unavailable PSHB Image Unavailable
PSHB Image Unavailable PSHB Image Unavailable



HELP STOP THE SPREAD
Infested and dead trees are a breeding ground for shot hole borer (PSHB). Recent tests Indicate that ONE heavily infested tree contains over 100,000 beetles. Dead trees need to be removed and disposed of responsibly.



How to dispose of
infested plant material:

  • Cut infested branches into small pieces.
  • Put into refuse bags and seal.
  • Keep in direct sunlight, the heat from the
    sun will kill the insect and its larvae.

Or

Burn on site.
(Large quantities of infested wood may not be burnt in an urban area)

Or

Consult a tree specialist.

Or

Chip and compost.



Further Reading:


The Conversation
A tiny beetle and its deadly fungus is threatening South Africa’s trees
by Wilhelm de Beer

Read Here

FABI Research Feature
The Polyphagous Shot Hole Borer

Read Here

Australasian Plant Pathology
The polyphagous shot hole borer (PSHB) and its fungal symbiont Fusarium euwallaceae:
A new invasion in South Africa
by T.Paap et al

Read Here