An introduction to the Shot Hole Borer Beetle
An introduction to the Shot Hole Borer Beetle Photo: Trudy Paap
Background on Borer Beetles 99% only feed off dead plant matter Only 10 spp enter living tissue 1) Bark Borer Beetles - layer between bark and wood 2) Ambrosia Borer Beetles Bore into wood material of plants Live mostly in softer year lines of the wood Very specific relationship with a fungus Generally associated with specific tree host
The Polyphagous Shothole Borer Beetle (PSHB) Euwallacea fornucatus Fungal symbiont (the real threat to the trees): Fusarium euwallacea Polyphagous = 'eating in excess' Origin: Asia Arose as a pest in USA and Israel killing Avocado trees.
The Polyphagous Shothole Borer Beetle (PSHB) If host it bores into is suitable creates brood galleries for young Then introduce F. euwallaceae colonises walls of galleries and used as food for brood and adults F. euwallaceae then invades the vascular tissue of tree - branch die back, vascular wilting and death of many trees
The PSHB in South Africa Officially first recorded by Trudy Paap at the Kwazulu Natal National Botanical Garden in 2016 Subsequently discovered in Johannesburg and Pretoria Most recently ID'd in George, Knysna and Tsitsikamma
South Africa Pietermaritzburg Durban
REPRODUCTIVE HOST TREES NON-REPRODUCTIVE HOST TREES English Oak Blackwood (A. melanoxylon) Avocado Liquid ambar Boxelder Coral (Erythrina caffra) London Plane Chinese maple Japanese maple Virgillia diviricata? ? Fig Grapevine Guava Lemon Loquat Mulberry Olive Orange Peach Pecan Plum spp. Orchid tree (Bauhinia) Ash (Fraxinus spp. ) Camellia spp. Camphor Elm spp. Frangipani Kapok Oak spp. Silver birch Willow Euc. camaldulensis Honey locust Flame tree (Brachychiton) Magnolia grandiflora Salix spp. Castor bean Jacaranda mimosifolia? Syringa (Melia azedarach) Pepper tree Poplar Verbernum Acacia (Vachelia) spp. Bauhinia galpinii Bosvlier (Nuxia floribunda) Buddleja saligna (witolien) Combretum spp. Erythrina spp. Geelkeurboom (Calpurnia aurea) Huilboerboon (Schotia brachypetala) Kiepersol (Cussonia spicata) Kruidjie-roer-my-nie Monkey plum (Diospyros lycidioides) Podocarpus falcatus Podocarpus henkelii Searsia spp. Terminalia sp.
The PSHB in South Africa – Non Indigenous Hosts AGRICULTURAL TREES -Avoes, macadamia, pecan, peach, orange, grape vine, fig (indigenous figs? ? ) -Rooibos? Honey bush? OTHER -Maples, Oaks, Planes, Poplars, Liquid ambers, Willows -Castor bean (Melianthus major? ? )
The PSHB in South Africa – Indigenous Hosts PREVIOUSLY RECORDED - Coral Tree, Vachellia seiberiana, Combretum sp. , Diospiros whytianna, Cussonia spicata, Afrocarpus falcatus RECORDED AT THE GRBG - Podylaria calyptrata, Virgillia sp. , Diospyros sp. , Protea mundii, Leucodendrom conicum, Psoralea pinnata, Rapanea melanophloes, Afrocarpus falcatus.
The PSHB in South Africa – Podylaria calyprata
The PSHB in South Africa – Protea mundii
The PSHB in South Africa – Keurboom
The PSHB in South Africa – Leucodendron conicum
The PSHB in South Africa – Diospyros sp.
Current Control Methods Cut and burn (on site) Chip and compost (under clear plastic/ 30: 1 C N content) Cut and solarise Lures (expensive and not effective – rep in situe) Fungicide/pesticide mixes (not properly tested)
My Opinion Plants natural habitat vs. current location (genetic diversity) Plants health (weedeater damage etc) Plant age and ecological function Tool sanitation Remove reproductive hosts
Issues we face Educate small scale landscape and garden services Try stop firewood dispersal The beetle in nursery saplings Looking at tree spp that are NOT getting effected
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