Just days after it was announced that a "solution" has finally been found to the tree-killing beetle problem in the country, a group of scientists slammed on the breaks.
Professor Wilhelm de Beer who leads the polyphagous shot-hole borer (PSHB) network of 17 academics at the University of Pretoria, says they have not started tests on the much-debated latest product by Pan African Farms (PAF) in Parys in the Free State.
"I am not saying the product does not work," contends De Beer. "What I am saying … is that the evidence provided is not at all sufficient to back claims about the product. The design of the experiment is not good enough. The experiments done in a lab and field are insufficient and claims or conclusions are misleading."
'How can he judge?'
But PAF CEO Pieter Meyer responds, "I gave him (De Beer) samples and I don't know if they did tests, but where is his evidence? How can he judge? He has not even seen all the research."
De Beer also questions the registration process of the product. "I am actually amazed that the product has been approved, but what people must also realise is that it only got temporary approval for experimentation. But now someone might be misleading people big time and make a lot of money."
There is indeed "a lot of interest", according to Meyer, who says they have many orders for the product and feedback has been positive. "We are operating within the confines of the law. When it comes to Prof de Beer, I really struggle to control myself. But you don't fight fire with fire. I am irritated. The solution is definitely not to start chopping off first a hundred trees, then a million and then 10-million. If we can just save half it's worth it," says Meyer.
Silviculture specialist Dr Jaap Steenkamp who manages PSHB treatment in George and surrounds, believes the most important thing when you find evidence of the beetle is to not panic, but approach the problem in a logical way.
He says everybody is looking for a solution and there are many treatments, including sound frequency to repel the beetles, that might be working.
"We have been very successful and have saved many trees… We use a variety of products to make a cocktail…" says Steenkamp.
"We only started using the PAF product again on 1 August, since the preferred method of application is systemic contact treatment (injection) which can only occur during the growing season, and it is working. But the product PSHB Fungicidal only addresses the fungi (or beetle food) and leaves the beetles untouched. In my opinion they look for new trees long before they starve to death," says Steenkamp.
He cautions against an attitude of "Not in my garden!". "It is very important not to go cowboy or cut off an infected tree and just throw it on the trailer and speed all the way to the dump," he says. This will only contribute to the spread of the beetle, he adds.
What about burning?
Combustion of moist timber is slow and may contribute to spread PSHB, says Steenkamp. "Incinerate is different but infected trees that are felled must be sprayed with Cypemethrin which is available at the local co-op."
That being said, treatment is better and cheaper than felling, Steenkamp believes. He advises to observe infected trees logically, monitor them closely and treat with both an effective insecticide and fungicide and preferably various methods of application including spray and injection.
Luckily the impact on indigenous trees, he says, is not big except for susceptible species like yellowwood. The beetles still prefer invasive hosts but fruit trees and especially avocado trees are very susceptible.
Tell-tale signs of the borer beetle are little holes of 1mm in diameter, dark spots and white excretion. "It can look like a shotgun was fired at the tree. Trees with a rough bark are tougher to identify. Infected and untreated trees may die within months. We have even found infestation in bonsai," says Steenkamp.