1 July, 2019
Eyes peeled for the Shot Hole Borer
and foresters are keeping their eyes peeled
for evidence of the destructive polyphagous
shot hole borer (PSHB) in plantations.
beetle has been spotted on one eucalyptus
tree in Sandton and a few roadside wattles
in the Southern Cape, but on no other
forestry species in South Africa.
is certainly concern about its effect on
plantations, although there is no evidence
of the impact yet," said Professor Wilhelm
de Beer of the Forestry and Agricultural
Biotechnology Institute (FABI) at the
University of Pretoria. "We need to
carefully monitor the situation and are
working with the forestry industry, which is
continuously monitoring its plantations.
biggest concern is the indigenous forests.
We are seeing the borer in more and more
borer is from South-East Asia and has no
natural predators in South Africa. It is
known to have migrated only to South Africa,
Israel and California, where it was found in
a few pine trees and caused a native willow
species to be entirely removed from a river
South Africa it is having a devastating
impact on tree species including the oak,
plane and box elder in Johannesburg, Durban,
Bloemfontein, Pietermaritzburg, Knysna and
George. To scientists' great concern, it has
moved from some of these cities into many
species of indigenous tree in nearby
Tree Protection Co-operative Programme, a
co-operative research project between the
University of Pretoria and private forestry
companies, focuses on all pest and pathogen
problems facing forestry plantations. The
programme has grown to become
internationally recognised as the strongest
in the world in dealing with such
challenges. Researchers from the programme
continuously monitor forestry trees and are
incorporating surveillance for the shot hole
borer into their work.
network of 18 academics from eight
universities, called the PSHB Research
Network, is investigating the beetle's
impact on avocado, macadamia and pecan nut
trees, some other fruit crops, natural
forests, urban forests and plantations.
shot hole borer tries to make its home in
many trees species but leaves most of them
untouched. It is generally indiscriminate,
as it does not eat timber but feeds on a
fungus that it introduces into its host
tree. It is the fungus, which grows in
tunnels made by the borer, that kills the
trees develop wilted brown leaves on
infested branches. The most obvious sign of
an infestation is branches with brown stains
around each hole where the borer has
penetrated the tree.
of affected trees is extremely challenging.
The entire tree must be removed and
carefully disposed of, as the beetles can
emerge and fly away to infest other trees.
The Department of Agriculture,
Forestry and Fisheries is in the process of
declaring the beetle an invasive pest, which
will allow emergency registration of
Source: Dolphin Bay Chemicals