Weevils and hoppers released to halt water lettuce crisis on the Vaal
In addition to the release of weevils and hoppers, there will be a modest application of approved and permitted herbicides, Rand Water said

Rand Water will be releasing weevils and hoppers into the Vaal River today, Thursday 15 February.
Rand Water explained that these are small insects that eat the water lettuce that has become a crisis on the Vaal river. Weevils eat water lettuce, while hoppers eat hyacinth.
The increasing incidence of water lettuce in the Vaal River can have a devastating impact that range from fishing (which poorer communities need to provide a meal) to agriculture, where irrigation equipment clogs, environmental devastation, loss of tourism potential, job creation, property development and local economies.
Rand Water in a statement confirmed that in addition to the release of weevils and hoppers, there will be a modest application of approved and permitted herbicides that will be released into the water under the guidance of senior and qualiied Rand Water officials.
The introduction of chemical control is a short-term internvention and will be followed by non-chemical medium and long-term interventions, Rand Water said.
Photo credit: Vaal River Rats SA
On Wednesday 14 February spraying of the herbicide Glyphosate on the Vaal’s water lettuce and hyacinth continued at Luciana Country Estate which is situated close to the barrage wall, said Andrew Surtees of Vaal River Rats SA.
Over the past two weeks incredible action has been seen by the community to address the water lettuce crisis on the Vaal.
Vaal River Rats SA on their Facebook page said that they and the community still encourage all to also participate in removing the water lettuce manually as was seen over the past two weeks with incredible action taken to address the crisis. “The people have been nothing short of incredible through this process,” they said in their post.
Rand Water earlier confirmed that an integrated approach including physical removal, biocontrol and chemimal application will be followed in managing the water lettuce and hyacinth crisis.
In a statement Rand Water said the spraying of Glyphosate is done by professional crop sprayers and drone operators. Spraying started on 13 February.
Rand Water stated that the application of all herbicides used on the project has been approved by both the Department of Forestry, Fisheries and the Environment, and the Department of Water and Sanitation South Africa “and they are set at a sub-lethal dose because we are implementing an integrated approach”.
According to Rand Water the sub-lethal dose increases the sugar and carbohydrate contents of the Pontederia crassipes plant making it more palatable for the biocontrol agent. “The specific formulations of the glyphosate that were recommended are made based on expert opinion and research, and field work is being monitored for compliance at present.”
“Although biocontrol agents are already on the Vaal Barrage, additional biocontrol agents will be released on 15 February (should weather conditions permit it). They will hopefully be released in the upper reaches of various water bodies (stream inlets) on the Barrage as well as in some selected areas between reed beds on the Barrage, Rand Water concluded.