Cape Town - An invasive beetle, already found across eight provinces, continues to infest and destroy local trees, and researchers have worked for more than three years to find a solution to this environmental harm.
The polyphagous shot hole borer (PSHB) beetle comes from Southeast Asia and was first discovered in South Africa in 2017. It has already caused devastation in gardens, parks and urban forests. Durban, Pietermaritzburg, Hartbeesfontein, Bloemfontein, Ekhurhuleni, Jankempdorp, Sandton and Sedgefield are among some of the hardest hit areas.
Stellenbosch University Department of Conservation Ecology and Entomology in the Faculty of AgriScience doctoral research student Heather Nependa said: “The female beetle infested trees with a fungus and fed on this fungus, not the wood. The fungus invades the tree’s vascular system, preventing nutrient and water absorption, which eventually kills susceptible trees.”
She said the loss of these trees is leading to the loss of habitat for animals, prevents air pollution removal, prevents the control of water run-off and soil erosion, and the prevents regulation of climate through Co2 sequestration.
“Extra vigilance in terms of monitoring and experimentation is required during this summer, as we learn more about the biology of the beetle and investigate various control and management options,” she said.
The research site of the beetle is at a 320-year-old Vergelegen wine estate in Somerset West, which has pioneered agricultural and horticultural testing.
A monitoring and early detection scheme, to learn more about the beetle and how it spreads, will be discovered through the research.
Visitors to the site on the estate will be able to spot two types of traps used to monitor and collect the PSHB. The simplest design uses plastic bottles, fitted with a chemical lure tied to steel rods. The second type of trap is 3D-printed and secured over holes made by the beetles on the trees. All traps are inspected every two weeks and contents are delivered to the university.
Cape Argus