Timber iQ February - March 2019 // Issue: 42 | Page 40

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Measuring a little over 2mm, the beetle tunnels through the tree leaving larvae and fungi that may destroy the tree.
Tiny beetles fire deadly
shots at our trees
Recently discovered in South African trees, the polyphagous shot
hole borer (PSHB) is a beetle that's infesting tree species worldwide.
We find out more.
Compiled by Ntsako Khosa
N
ative to Southeast Asia, environmental experts says
that these beetles, also known as Euwallacea
fornicatus, are a troublesome species that are able to
cause a great deal of trouble to the environment.
THE PSHB
These beetles are about 2mm long and associated with
different types of fungi. One of these fungi is called
Fusarium euwallacea. The shot hole beetle shares a
symbiotic relationship with this fungus, as this fungus is the
beetle’s main source of food in addition to it being the main
cause associated with the wilting of trees. The other types
of fungi are believed to help the beetle’s colonisation of
newly infected trees.
‘The borer was discovered in 2017 by Dr Trudy Paap of
the Forestry and Agricultural Biotechnology Institute (FABI)
38 FEBRUARY / MARCH 2019 //
initially discovered the shot hole Borer beetle in South
Africa. On a routine study for diseases in KwaZulu-Natal
Botanical Gardens in Pietermaritzburg, Paap found a series
of infested trees. This led to the identification of the beetle
in addition to the regions in which infestations are taking
place,’ explains the FABI website.
According to FABI, the discovery of this beetle and fungus
in South Africa is of major concern to foresters, farmers and
landscapers, as these organisms are known as aggressive
tree killers. In 2017 the Johannesburg Urban Forest Alliance
estimated that up to 100 000 trees in Johannesburg could
already be infested, with the infestation spreading fast.
The PSHB along with its fungus has caused tremendous
damage to the trees in the US, specifically California, in
addition to regions in the Middle East. Moreover, the beetle
See more on page 40
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