Shoalhaven Council uses beetle to combat invasive aquatic weed

Council has released biological control weevils into Flatrock Dam, west of Nowra to help combat the aquatic floating weed, Salvinia molesta, which has inundated the waterway.

The aim is to deliver an environmentally sustainable approach to managing the invasive aquatic weed.

Salvinia molesta is a floating aquatic fern, native to south-eastern Brazil, which has a phenomenal growth rate, doubling its dry weight in two and a half days when conditions are right.

Salvinia blankets the water surface reducing light levels, temperature and oxygen in the water below.

Read more:

This has profound effects on communities of native plants and animals in the water.

It also interferes with animal access for drinking water, human access for swimming and boating, reduces water quality and blocks pumps.

The weevils, Cyrtobagous salviniae, have proven to be a successful biocontrol agent after trials by CSIRO scientists in the 1980s.

Shoalhaven Mayor Amanda Findley said council's Environment Services Team employ biological control measures to effectively management weeds in the Shoalhaven.

"As residents or visitors to the Shoalhaven, we are lucky to enjoy an abundance of pristine natural environments and that's why it's important council uses innovative weed management practices in the interest of preserving that natural ecosystem," Cr Findley said.

"Council also supports research, development, production and distribution of regionally appropriate biological controls and continues to engage and educate the local community on the important role biological controls play in weed management.

"As aquarium or ornamental pond plants can be a means of spread for aquatic weeds, please take care when disposing of aquatic plants."

Salvinia is a sterile hybrid and only reproduces vegetatively from broken-off pieces or whole plants being moved on boats or fishing equipment or washed from one water body to another in floods.

Successful management of Salvinia relies on early detection, action and implementation of an integrated control program.

For more information on biological controls to manage weeds, contact Shoalhaven Council's Environment Services Team on 4429 3111 or visit council's website, www.shoalhaven.nsw.gov.au

We depend on subscription revenue to support our journalism. If you are able, please subscribe here. If you are already a subscriber, thank you for your support.