Weevils clean up Condor Lakes
THEY’RE tiny, ravenously hungry and should be considered extremely dangerous – to the aquatic weed called salvinia, anyway.
About 200 little weevils have been put to work at Hervey Bay’s Condor Lakes to help clean up the salvinia weed, which has infested the waterway.
Juliet Musgrove, a Fraser Coast Regional Council land protection officer, said the council’s smallest new workers fed on the leaves, stems and roots of salvinia then laid their eggs in the stems.
The larvae feed on the stems and leaf buds, finishing off the plant.
“These weevils are particularly successful because they feed only on salvinia and have no adverse effects on any other plants or animals in the ecosystem,” she said.
Ms Musgrove said if weevils were not used the salvinia would eventually take over the lake from bank to bank and it would be very harmful to wildlife.
“We have discovered that if we can minimise salvinia, the waterways stay healthy but if it spreads out of control it cuts out the light to the animals in the water, increases evaporation by up to 400 per cent and stops wildlife moving freely through the water.”
Condor Lakes is home to a wide range of wildlife, including cranes, ibises, swamp hens, magpie geese, turtles, fish and ducks.
Weevils love the Queensland climate and enjoy this time of year best, reproducing in temperatures ranging from 27 degrees to 35 degrees.
Weevils were introduced to Australia from Brazil in 1980.
They were first released into a heavy infestation of salvinia at Lake Moondarra, near Mount Isa.
By mid-1981 the beetle had reduced the weed to a few small patches – and the council is hoping to see the same results here on the Fraser Coast.
The weevils used by the Fraser Coast Regional Council were bred by the Gympie Regional Council and supplied to the Fraser Coast in exchange for a $500 annual donation to help with the upkeep of the tanks, making the control program cost-effective as well as environmentally safe.