Tiny beetle is killing SA's trees – and nothing can stop it

[Richprins]

2018-09-05 07:41

Riaan Grobler


A beetle smaller than a sesame seed is killing huge trees throughout South Africa, and little can be done to stop it.

The polyphagous shot hole borer, a native of southeast Asia no bigger than 2mm, has found its way to South Africa and is infesting trees at an alarming rate.

According to Professor Marcus Byrne, an Ig Nobel prize winner and entomologist at the University of the Witwatersrand, the beetle bores tunnels into tree trunks where it spreads the fungus Fusarium euwallaceae, which effectively cuts off the trees' vascular system, causing them to die.

"It's an ambrosia beetle, which means it carries a fungus which it feeds its babies on. When it introduces that fungus into trees that have never experienced it before, it threatens those trees with illness or death."

Byrne says no one truly knows how the beetles made their way to South Africa.

"We happen to be a very connected world and trade today allows for the movement of goods all around the world. We're not very good at screening these animals that hitchhike around the world on our consumer goods."

No solution yet

According to Byrne, there isn't a solution to rid trees of these beetles once infested.

"You can apply a fungicide, but the scale at which you would have to apply it is just ridiculous.

"There are lots of snake-oil merchants that are trying to sell what they see as solutions, but none of these works."

The local beetle infestation was first noticed last year by Dr Trudy Paap – a postdoctoral fellow at the Forestry and Agricultural Biotechnology Institute at the University of Pretoria – in the KwaZulu-Natal National Botanical Garden in Pietermaritzburg, and it has since been found nationwide, including in Johannesburg and as far as the Northern Cape.

Johannesburg has what is considered one of the world's largest urban forests with an estimated 10 million trees.

According to Andrea Rosen, co-director of the Johannesburg Urban Forest Alliance, up to 100 000 trees in Johannesburg could already be infested, and the infestation is spreading fast.

"The polyphagous shot hole borer is of grave concern," Rosen told News24 on Tuesday.

"Some projections go up to half a million trees that are affected in Johannesburg alone, which is a substantial part of our urban forest canopy."

Rosen says there is no effective treatment for infested trees apart from cutting them down and chipping the wood or burning it.

A local company, Pan African Farms, has developed a solution that has shown to be effective in laboratory conditions but is pending emergency registration before it can be used on actual trees. Rosen hopes that it will be available within the next two months.

According to Rosen, many trees in Johannesburg residents' gardens could be infested without them knowing about it.

"People only realise something is wrong when their trees die from being so heavily infested.

"These trees then need to be cut down."
beetle
Tiny holes in the bark of an infested tree. (Supplied)

Signs of infestation

Signs of an infestation include wilted or missing leaves, dead or dying branches, as well as tiny and randomly spaced holes in the bark. These holes could have staining around them, or a white powder or gum-like blobs oozing from them.

Julian Ortlepp, owner of tree-care company TreeWorks, has been trying to rid trees of the beetle by injecting systemic treatment directly into trees, but says there isn't a sure-fire solution just yet.

According to Ortlepp, the treatment developed by Pan African Farms sounds "promising".

"It is sprayed on to the surface of the tree and penetrates the tree using lipids. In the laboratory the trials have been quite successful," Ortlepp told News24.

Ortlepp says the beetles have infested large parts of Johannesburg's northern suburbs, the West Rand, as well as Bedfordview.

"It's widespread across Johannesburg as well as the rest of the country."

Suburban trees that are affected include exotic trees such as the Japanese and Chinese maple, London plane, English oak, kapok and liquid amber. Indigenous trees including the coral tree and the paperbark are also affected.

On Monday, the Northern Cape department of agriculture, land reform and rural development issued a statement in which it said it was "concerned about the occurrence of a new pest that occurs on the pecan nut trees in the Vaalharts area".

The department warned farmers in the area to "be on the look-out" for the beetle as it can infest "important crop tree species such as orange, peach, grapevine, avocado, macadamia, pecan trees as well as forest trees such as the cabbage tree, monkey plum, common coral tree and honey flower".

The department said infested trees should be reported "or alternatively cut down and chipped".

City Parks 'unresponsive'

In Johannesburg, attempts to engage Johannesburg City Parks and Zoo (JCPZ) have been largely unsuccessful, according to Rosen and Ortlepp.

In April, various stakeholders met with JCPZ officials, including the member for the mayoral committee for community development, Nonhlanhla Sifumba.

A media statement was issued following the meeting in which Sifumba undertook to do "a thorough assessment to understand the true extent of the infestation, train personnel to monitor, dispose of trees and to identify the borer and other fungal hosts that accompany the beetle, put in place a designated area for the controlled dumping and burning of trees, and ensure that a tree replacement strategy is in place".

"None of this has happened," Rosen told News24.

"We believe it is highly irresponsible for the City not to put out an alert."

According to Ortlepp, "we are willing to assist the City but they have not been forthcoming with information. We have not heard anything from them since our meeting. It is very frustrating."

There's an app for that

Johannesburg resident Hilton Fryer has developed an app for residents to report infestations after he had been battling to save infested trees in his own garden.

"I quickly realised that service providers didn't really know how to deal with this problem," Fryer told News24.

"I quickly developed a fair amount of knowledge about the problem that I then decided to share with the public via my website."

Fryer developed a tool for members of the public to report infestations on his website, which ultimately led to the development of the app.

Called "Tree Survey", the app is available on both iOS and Android platforms.

It was soft-launched on September 1 and had by Tuesday received 150 reports of infestations.

Fryer calls in each infestation himself.

"I have spoken to the business development manager of City Parks and I am trying to motivate them to assign an individual to work on the system to improve the efficiency in responding to public notifications. The system I developed allows [JCPZ] to communicate directly with the resident."

Fryer told News24 that he knew from indirect information that JCPZ was planning to act on the issue, "but my biggest concern is that they are not communicating with the public".

"They've missed a great window of opportunity to develop an action protocol as we approach spring."

According to Rosen: "If nothing is done, we stand to lose up to 30% of our tree canopy.

"Added to that, dead trees falling on people is a real danger to the public."

Numerous attempts to reach JCPZ were unsuccessful. A spokesperson's cellphone went straight to voicemail and calls to landlines went unanswered.

https://www.news24.com/Green/News/tiny- ... t-20180904

[Lisbeth]

Tiny Beetles Cause A Giant Crisis

21.09.2018 - Sipho King

A plague of tiny beetles is tearing into our trees and killing them. The unprecedented crisis has led to towns, cities, companies and universities scrambling to find an urgent solution.

The innocuous-looking villain is the 2mm-long shot hole borer. An invasive alien species from Asia, the borer burrows deep into trees to create a nest for its eggs. It then secretes a fungus (Fusarium euwallacea) to feed its larvae.

The fungus feeds on the capillaries of its unwilling host and starves the tree of water and nutrition.

The first sign that a tree has been invaded is shotgun-like holes on the outside. Dark-red resin then starts to ooze from the holes.

A single tree can host up to 100 000 beetles.

In 2013, huge oak trees in Knysna — which had survived two centuries of fire, flood and drought — began inexplicably to crack and break apart. Large branches simply fell onto pavements, cars and buildings.

In nearby George, the municipality had to warn residents and tourists to “take a look at the tree before you walk, park, stand or picnic under it”.

Knysna responded with chainsaws, cutting the trees down and offering the chunks of wood to anyone who would take them. The municipality did not know then that with its minute, see-through wings giving it limited range, the beetle relies on humans to move it over any great distance.

This is precisely how an insect from Vietnam has been able to kill trees in California, Israel and now South Africa.

In Sandton, Johannesburg, mature trees started dying in early 2015. People chopping them down would often sell them as firewood in Soweto. Shot hole borer has now been found in some of the 250 000 trees that City Parks has planted in that suburb. They will start to die this summer.

In Lanseria, to the west of the city, beetles from Sandton firewood dumped there crawled into nearby oak trees and infected them too.

Nobody knew what was killing the trees. It was only by chance — and a year later — that Dr Trudy Paap from the University of Pretoria (UP) managed to piece the mystery together.

While doing a routine survey of diseases and pests at the National Botanical Gardens in Pietermaritzburg, she spotted the shot-like holes in a row of trees.

Dust around the holes indicated that something had drilled its way inside. DNA testing of the sap that was oozing out of the holes showed that it contained the same fungus found with the beetles in California’s trees.




With the cause identified, a solution needed to be found. However, this is the first invasive species that is polyphagous, meaning it feeds off a variety of tree species.

Professor Wilhelm de Beer, also from UP, who is leading the research into a solution, says this makes it an unprecedented problem: “Normally, infestations go for eucalyptus or avocado. This goes for everything. We’ve never dealt with anything like it before.”

A particular problem is the fact that the borer is targeting the giant exotic trees that often grow in cities. This, too, has never occurred before.

It means trying to get everyone involved in tackling the problem, which in turn means many solutions and jurisdictional issues.

Just getting money to work out what to do with the beetle is a problem, says De Beer.

Research across sectors will have to be pooled to work out how to handle the epidemic.

A crucial step is an emergency declaration by the department of environmental affairs so that solutions can be fast-tracked — chemical or biological responses can be implemented speedily and controls tightened.

Nurseries will be compelled not to sell plants containing any signs of the pest.

In cities, some groups have taken to spraying chemical cocktails on affected trees. However, the insects bore too deeply to be affected. The spray is also potentially poisonous for humans, animals and other plants.

Best practice is to bring in the beetle’s natural predator. In this case, it’s a Vietnamese wasp small enough to enter the invasion cavities.

However, this needs to be done carefully so that those predators don’t become a problem in themselves.

Dr Guy Preston, at the department of environmental affairs, says the rate at which the beetle population is spreading is a real worry.

“We could see a situation where you need to cut down the big trees in the northern suburbs [of Johannesburg].” Pretoria’s purple-blossomed jacarandas could also go.

Out of the 80 major tree species in South Africa, 20 are perfect hosts for shot hole borers. For now, the only working solution is to cut down trees when they are infected and to burn the wood.

Homeowners are being told to cut dead trees into small pieces, seal them in plastic bags and place them in direct sunlight to eradicate the bug and its fungus.

Cities are also setting up dedicated dumps where infected trees can be chipped.

If this is not done and an alternative solution not found soon, history shows that shot hole borers are relentless.

They have hit the American state of California dramatically in the past five years.

While shot hole borers infect living trees, other borer species inhabit fallen ones. Whereas these would usually be killed off by cold weather in the winter, rising temperatures and warmer seasons have ensured the beetles survive and thrive.

The beetles’ savage destruction has had a knock-on effect; dead trees have fuelled wildfires as well as fatal landslides because there are no longer enough roots to anchor the soil.

The infestation in California has only recently been brought under relative control. By immediately cutting down infected trees, the state has brought beetle numbers down to a level where they have a small negative effect.

[Richprins]

One good thing is that it seems not many indigenous species are targeted.?

[Dzombo]

I seem to recall seeing we are having a similar problem here.
Except these are our indigenous trees!

[Richprins]

[Lisbeth]

Rather scary

A few years ago it happened to the chestnut trees here, but they found a cure and now they are going strong again

[Lisbeth]

A tree infected by the polyphagous shot hole borer. Picture: Supplied

environment 10.8.2019 10:25 am

Finally: A solution to get rid of the beetle that is killing SA’s trees

A new technology developed by a South African company is the first to prove effective in killing the polyphagous shot hole borer, a tiny beetle that has been killing trees worldwide at an alarming rate.
The beetle, a native of southeast Asia, is no bigger than 2mm, but carries a fungus that kills trees. It has been spotted in every province except Limpopo and, until recently, there was no way to stop it.

But Parys-based company Pan African Farms has come up with a solution to rid trees of the borer.

The treatment got the go-ahead from the Department of Agriculture, Forestry and Fisheries in June, which means it can be used as an agricultural remedy.

Professor Marcus Byrne, an Ig Nobel prize winner and entomologist at the University of the Witwatersrand, earlier told News24 that the beetle bores tunnels into tree trunks where it spreads the fungus Fusarium euwallaceae , which effectively cuts off the trees’ vascular system, causing them to die.

“It’s an ambrosia beetle, which means it carries a fungus which it feeds its babies on. When it introduces that fungus into trees that have never experienced it before, it threatens those trees with illness or death.”

Byrne says no one truly knows how the beetles made their way to South Africa.

“We happen to be a very connected world, and trade today allows for the movement of goods all around the world. We’re not very good at screening these animals that hitchhike around the world on our consumer goods.”

Unique, eco-friendly and smaller than a cell

Piet Meyer, CEO of Pan African Farms, told News24 the company has managed to develop a unique, eco-friendly solution using nanotechnology.

“The core of our technology is nanotechnology,” Meyer says. “Our vesicle, as far as I could determine, is the smallest in the world at 10 nanometres.

“To give you some perspective: The smallest living cell is 10 microns. Our vesicle is 1,000 times smaller than that.

“That enables it to penetrate through most known barriers.”

Meyer says all fungi, including Fusarium, have a cell wall.

“This wall has always been regarded as impenetrable, but with our vesicles there’s an instant passage through that wall. The fungus can then be killed through a series of cellular attacks.”

And this is the only way to kill the polyphagous shot hole borer – by killing what it feeds on. Ultimately, the fungus is destroyed and the beetles die of hunger.

“After 24 hours of applying this to the bark of a tree, we could trace it to about 10 and a half centimetres into the tree. That distinguishes this product from anything else.”

Meyer says other fungicides used today are expensive, labour-intensive and become ineffective after a while.

Picture a tennis ball

The best way he can explain the vesicles, Meyer says, is to picture a tennis ball. That ‘ball’ is called an Anods – which stands for amphiphilic nano oil-delivery system.

“A tennis ball is hollow inside and surrounded by rubber. In the Anods, the ‘rubber’ part is then surrounded by fatty acids, and the hollow part is filled with the active ingredient needed to kill the fungus.”

According to Meyer, conventional pesticides are ineffective because of drug resistance as pests adapt, much like antibiotics in humans.

“But we have found suitable natural active ingredients that can destroy the Fusarium fungus. It is non-toxic and it won’t harm your tree.”

Meyer says, after application, the beetles pour out of trees in droves.

“We found that there was no trace of the fungus left.”

Grave concern

The local beetle infestation was first noticed in 2017 by Dr Trudy Paap – a postdoctoral fellow at the Forestry and Agricultural Biotechnology Institute (FABI) at the University of Pretoria – in the KwaZulu-Natal National Botanical Gardens in Pietermaritzburg, and it has since been found nationwide, including in Johannesburg and as far as the Northern Cape.

Johannesburg has an estimated 10 million trees. According to Andrea Rosen, co-director of the Johannesburg Urban Forest Alliance, the infestation is spreading fast.

“The polyphagous shot hole borer is of grave concern,” Rosen told News24 last year.

“Some projections go up to half a million trees that are affected in Johannesburg alone, which is a substantial part of our urban forest canopy,” Rosen said. According to Meyer, that figure could be as many as 1.8m trees in the greater Johannesburg area.

“In urban areas, municipalities will have to act quickly to stop the spread of the borer beetles and save the trees that have already been infected.

“Each female beetle lays 20 eggs at a time in the bark of a tree. The life cycle is around 40 to 45 days and 60% of the population is female. According to my calculations, in 10 months, a single beetle can multiply to 50 million. That is an alarming figure.

“What worries me is that the beetles could spread to the Kruger National Park and the Knysna Forest.”

Spreading all over SA

The beetle has also spread to Cape Town.

“The first sighting was confirmed on 3 April 2019 in Somerset West,” Cape Town mayoral committee member for spatial planning and environment Marian Nieuwoudt told News24.

So far, the identified infestation in Cape Town is limited.

“At this stage the only positive sightings have been confirmed in the Somerset West area. Recently a sighting 1km away from the first positive sightings has been confirmed,” said Nieuwoudt.

For now, urban residents who notice the beetle in their gardens can buy the product directly from Pan African Farms.

“We have priced it to be user-friendly. They can then apply it to municipal trees growing on their sidewalks too, until such time as municipalities start using it,” Meyer says.

“This is happening in the north of Johannesburg right now.

“In Bloemfontein, for example, members of the community got together and decided to tackle the problem themselves.”

Signs of infestation

Signs of an infestation include wilted or missing leaves, dead or dying branches, as well as tiny and randomly spaced holes in the bark. These holes could have staining around them, or a white powder or gum-like blobs oozing from them.

“It looks like the trees are weeping,” says Meyer.

[Lisbeth]

“We have priced it to be user-friendly. They can then apply it to municipal trees growing on their sidewalks too, until such time as municipalities start using it,” Meyer says.

When will that be?