Bitou Bush Under Assault

Illawarra Mercury

Thursday June 19, 2003

By DANIELLE WOOLAGE

BIOLOGICAL weapons, battles waged from beaches and experts abseiling into enemy territory are just some of the tactics used to try to eradicate a noxious weed that has invaded our coastline.

Yesterday an aerial assault was launched on bitou bush, the South African plant that was introduced to Australia more than three decades ago to stabilise sand dunes.

The aerial attack, which involved a helicopter spraying herbicide over more than 100ha of affected coastline, focused on hot spots at Port Kembla's Hill 60, Bass Point, Killalea and Seven Mile Beach.

Illawarra District Noxious Weeds Authority chief David Pomery, who led the attack, said aerial spraying was the only way to control heavily infested areas that were inaccessible from the ground.

``The aerial spraying of Round Up, applied during winter, at low rates, selectively controls bitou bush but leaves native vegetation unharmed," he said.

The South African weed is a prolific propagator with each plant producing up to 50,000 seeds. ``These are then spread by birds and foxes," Mr Pomery said.

``And the seeds can remain viable for up to 10 years, germinating at any time."

Mr Pomery said the use of sprays and biological controls, like the Leaf Roller moths, diminished the number of seeds produced by the bitou bush.

``Where you once got 50,000 you might get 20,000 after using controls," he said.

But because seeds can remain viable for a decade controlling bitou is time consuming and ongoing.

``Aerial spraying is a much more cost effective and successful way of removing bitou bush in inaccessible areas," he said.