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Despite its tiny size, the polyphagous shot hole borer should not be underestimated.

Originally hailing from South East Asia, it’s thought the polyphagous shot hole borer (PSHB) arrived on our shores via wooden pallets which had been used to ship goods.

Speaking to CapeTalk earlier this year, Professor Francois Roets from Stellenbosch University said they were found in Richards Bay as far back as 2012.

As it bores into a tree, the beetle spreads its fungal symbiont, Fusarium euwallaceae, which blocks the vessels and channels in the tree that would move water and nutrients around. This leads to the tree dying.

The PSHBs have now found their way to eight of our nine provinces and the economic impact could be massive.

A Stellenbosch University study puts the potential economic impact on the country at R275 billion over the next 10 years, and municipalities will bear the brunt of this cost if nothing is done to stem the tide.

The Western Cape is very much under fire. IOL reports:

In the Western Cape, the beetles were first spotted in Somerset West in 2019, and are estimated to have infested 10 000 trees in the Helderberg region to date…

The provincial Department of Local Government, Environmental Affairs and Development Planning said infestations have been confirmed in Plettenberg Bay, George, Knysna and Stellenbosch…

Roets believes that without a radical plan to curb the spread of the polyphagous shot hole borer, a town like Stellenbosch could lose as many as 20 000 of the famous old oak trees and plane trees which line the streets.

BusinessTech with further alarming stats:

The data shows that if nothing is done to halt its spread from 2020 to 2030, 65 million urban trees will have to be removed and safely disposed of…

“We need a national policy and coordinated strategy for municipalities to stop this beetle in its tracks,” [Roets] warns.

Worryingly, the full extent of the distribution of the PSHB in the Western Cape is unknown at this stage.

We reached out to Tyrone Yates, who has extensive experience in dealing with exterminating the PSHB, via a unique treatment:

Unfortunately this pest has been the cause of many large trees throughout our country having to be removed and destroyed. Namely Cape Town, especially the Southern Suburbs where there many large oaks and the like, as well as Somerset West.

Although the worst affected trees are mainly deciduous exotics like oaks, acers, London planes, poplars, and pin oaks, it also kills a number of our indigenous or endemic trees.

We have started treating trees systemically and have seen good results. This is not a cure but more a salvage. However trees that are beyond recovery have to be removed and destroyed immediately and mostly on-site.

He says the reason the destruction is done on-site is to prevent moving the infected tree and aiding the beetle’s spread into new areas.

To offset the loss of the destroyed tree, they then replace the unrecoverable trees with indigenous trees that are not affected by PSHB.

As a macadamia nut farmer himself, Tyrone says he is currently working on treatments for crops using existing fertigation units most farmers have in place.

Hopefully this this will eliminate fears of losing whole orchards. It is so sad to see so many majestic trees felled, leaving huge voids on our landscape. I’m proud to be able to help save as many of these magnificent trees as possible before we lose them all.

For further information on how his unique treatment works, you can reach Tyrone at tyrone@ocpc.co.za or 082 904 0709.

Programme manager of the Invasive Species Unit at the City of Cape Town, Chandre Rhoda, says residents can also report any sightings of the polyphagous shothole borer beetle via the Cape Town Invasives website.

[sources:capetalk&iol&bustech]