Defending Our Trees: The Battle Against the PSHB Infestation

In recent years, there’s been this growing concern for our trees – a sneaky villain called the Polyphagous Shot Hole Borer (PSHB) made its entrance in South Africa in 2012 and has been wreaking havoc ever since.

This tiny pest, not much bigger than a sesame seed, has been causing some major damage to trees in different parts. As the weather warms up this spring, these little troublemakers come out of their winter dormancy and become active, posing a real threat to our trees’ health and ultimately our ecosystem.

The Polyphagous Shot Hole Borer, or Euwallacea Fornicatus in scientific terms, is an invasive beetle with disruptive behaviour. It infiltrates trees, bringing along the harmful Fusarium Euwallaceae fungus. This fungus quickly spreads and negatively impacts the tree’s vascular system, preventing water and nutrients from reaching the leaves and branches of the tree. This, in turn, triggers wilting, branch dieback, and ultimately leads to the tree’s fatality. What’s of particular concern is the beetle’s rapid migration to new locations, compounding the problem. The fact that this beetle does not have any natural predators in the South African eco-system, makes it even more dangerous.

So, how do you know if your tree’s in trouble? Keep an eye out for a few signs:

  • small holes that the beetles make
  • leaves drooping
  • resin oozing out of holes
  • sawdust on the bark or at the tree’s base

Treating trees that are infected has sparked some debates, with differing opinions on how to go about it. The prevailing approach usually involves cutting down the tree and responsibly managing the area where these pests breed, which could mean using methods like chipping, incinerating, or smothering.

Here’s our strategy:

  • Detect and identify infected trees as swiftly as possible.
  • Evaluate the extent of the infection and decide whether removal or treatment is the appropriate course of action.
  • Trees severely impacted by the infestation are removed and disposed of to prevent further spread.
  • Some trees, like Plane Trees, display remarkable resistance and manage to thrive despite the infestation.
  • We’re not letting these resistant trees fall under the radar – they receive proper treatment.
  • For young trees with only a minor infestation, we intervene with treatment.
  • In cases of infected trees with dead branches, we trim those off and administer treatment to give the tree a fighting chance.
  • As a preventive measure, we apply treatment to high-value uninfested host species like Acer and Plane trees.
  • Our treatment regimen involves a combination of surfactant (which aids absorption), fungicide, and insecticide.
  • The goal of these treatments is to target both the PSHB bugs and the troublesome Fusarium Fungus.
  • Consistent follow-up treatments are essential, especially during the summer months.
  • Due to the complexity of the infestation and the influence of various natural factors, it’s important to note that guaranteed results are hard to come by, even though our strategy has seen notable success thus far.

For a no-obligation assessment of your trees, feel free to contact Joe at 082 792 4512.

Thank you for being a part of our Highveld Tree Fellers community. Until next time, remain ever vigilant, stay curious, stay inspired, and stay connected!