Shoalhaven City Council has released biological control weevils in Flatrock Dam West Nowra to deliver an environmentally sustainable approach to aquatic weed management in the area.
The weed Salvinia molesta is a floating aquatic fern that is native to south-eastern Brazil and 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. 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 City Council 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 eco-system”, Clr 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,” said Clr Findley.
“As aquarium or ornamental pond plants can be a means of spread for aquatic weeds, please take care when disposing of aquatic plants,” Clr Findley said.
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.