The tiny polyphagous shot hole borer has become increasingly problematic since it was first detected in South Africa in 2012. Not only has the beetle been destroying trees throughout the country, but it’s also set to leave its mark on South Africa’s economy.
Since 2012, when the beetle was first discovered in the country, it has spread to eight of the nine provinces in South Africa, meaning that it’s the largest current outbreak of this particular invasive pest in the world. But where exactly this beetle is making its impact known is what has also made it different from other invasive species; whereas most of the country’s notorious invasive species affect the rural areas, this tiny but powerful beetle will have its largest impact on trees in urban areas.
The estimation of its urban impact is the result of a collaboration between economists, ecologists and other scientists at Stellenbosch University (SU) and the University of Pretoria (UP), reports Business Tech. The team used a modelling approach based on forecasted impacts to illustrate possible future impacts and damage if nothing is done to prevent further spread of this invasive species.
The current damage is already significant. In Somerset West, more than 10 000 trees have already been infected since it was first detected four years ago, and some trees are now dying. Prof Francois Roets, an ecologist in SU’s Department of Conservation Ecology and Entomology and one of the co-authors, said a tree-rich town like Stellenbosch stands to lose 20,000 of the big old oaks and iconic plane trees lining its streets.
The data gathered in the collaborative study shows that if the spread of the species is not slowed down between 2020 to 2030, an estimated 65 million urban trees will have to be removed and properly disposed of. The potential economic impact of the beetle’s damage could reach up to R275 billion, said the researchers.
Prof Martin de Wit, an economist at SU’s School for Public Leadership, opined on the need for a “national policy and coordinated strategy for municipalities” to prevent the beetle’s spread. “To date, the polyphagous shot hole borer is not yet listed under the Alien and Invasives Species Regulations, making it difficult for municipalities to react effectively,” said Prof Martin de Wit.
Prof Roets further explained why it’s been such a struggle to control the spread of the beetle. “To date, there is no thoroughly tested and approved insecticide or fungicide registered in South Africa to treat infestations of the shot hole borer effectively, at least not for urban trees. Anyone who tells you they will save your tree with chemicals and fungicides is likely lying and will be breaking the law,” said Prof Roets.
He also added: “A coordinated strategy to deal with the invasion in South Africa will require a revision of legislation and the creation of policies relating to biological invasions. Currently, there is no coordinated management of invasive species in urban ecosystems, a critical oversight.”
If you want to know more about this tiny destroyer, click over to polyphagous-shot-hole-borer.co.za where you can learn how to identify the beetle, how to know if your trees are infected, what steps to follow to treat an infected tree, and learn how to prevent the spread of the species.