Monday, 17 August 2015

Aliens committing suicide

Rust fungus creating havoc:

During the nineteenth century Acacia seligna, better known as Port Jackson, was introduced to the Western Cape for soil stabilisation. It was also deemed to be beneficial as animal fodder and for fuel wood. It must have seemed a good idea at the time.

This alien tree soon started invading the delicate fynbos systems of the Cape and there was no stopping it. Both physical and chemical control failed miserably as the Port Jackson marched forth relentlessly on its road of destruction.

In 1987 a rust fungus was introduced, which infected only the Port Jackson and no other species. The fungus itself does not kill the plant, but invokes a potent infection stress. In reaction to this severe stress the Port Jackson forms galls, with which it eventually strangles itself.

The spores of the fungus are spread widely by the wind.

The life expectancy of a Port Jackson tree has dropped from fifty years to less than ten...

On a different front a specific weevil which feeds only on the seed beds of these trees has also been recently introduced.

Hopefully the fynbos will soon reclaim these barren areas.

1 comment: