PSHB is an ambrosia beetle, about 2mm long, which makes tunnels in the wood of trees. The female beetles infest trees with a fungus — they feed on this fungus, not the wood — and it's this fungus that kills the trees in the end.
What makes this beetle unique is that it can infest so many different species of trees. Most other beetles are quite specific – for example, they go for pine trees or avocado trees, not everything. This beetle is absolutely relentless: it will try any tree, although in many trees it is unsuccessful.
This includes both exotic and local varieties; about 35 of the 80 are indigenous. Scientists are monitoring the beetle’s spread into native forests.
Almost every species of tree has different signs of infection. Some trees have a white powder, some a brown sap and others just a drop on the trunk.
Now that the beetle is in Somerset West, it is my prediction that there will be very, very few oaks left in the Cape Peninsula based on what we have seen in George, Knysna and Johannesburg. Streets of trees are already dying.
In Johannesburg, for example, we know that the Jacarandas and white stinkwoods are quite common and those are not infected, though sometimes they have a few holes.
We are still doing more research to be certain which species are not affected.
Scientists are doing experiments to find out how to prevent PSHB infection and how to get rid of it, but there are no positive scientific results unfortunately.
(That said, Johannesburg City Parks maintains that homeowners should keep their trees well fertilised and watered, as "a healthy tree is more like to withstand the effects of the PSHB".)
A reproductive host tree is a tree in which a beetle is successfully established and starts breeding.
There are 20 different species that have been identified as reproductive hosts; English oaks, London planes and Chinese and Japanese maples become heavily infested.
(The wood from infested trees that have been cut down must be dealt with carefully in order not to inadvertently spread the beetles to other trees, or other areas. To find out how to properly dispose of it.
What makes this beetle unique is that it can infest so many different species of trees. Most other beetles are quite specific – for example, they go for pine trees or avocado trees, not everything. This beetle is absolutely relentless: it will try any tree, although in many trees it is unsuccessful.
This includes both exotic and local varieties; about 35 of the 80 are indigenous. Scientists are monitoring the beetle’s spread into native forests.
Almost every species of tree has different signs of infection. Some trees have a white powder, some a brown sap and others just a drop on the trunk.
Now that the beetle is in Somerset West, it is my prediction that there will be very, very few oaks left in the Cape Peninsula based on what we have seen in George, Knysna and Johannesburg. Streets of trees are already dying.
In Johannesburg, for example, we know that the Jacarandas and white stinkwoods are quite common and those are not infected, though sometimes they have a few holes.
We are still doing more research to be certain which species are not affected.
Scientists are doing experiments to find out how to prevent PSHB infection and how to get rid of it, but there are no positive scientific results unfortunately.
(That said, Johannesburg City Parks maintains that homeowners should keep their trees well fertilised and watered, as "a healthy tree is more like to withstand the effects of the PSHB".)
A reproductive host tree is a tree in which a beetle is successfully established and starts breeding.
There are 20 different species that have been identified as reproductive hosts; English oaks, London planes and Chinese and Japanese maples become heavily infested.
(The wood from infested trees that have been cut down must be dealt with carefully in order not to inadvertently spread the beetles to other trees, or other areas. To find out how to properly dispose of it.
