In an effort to protect freshwater ecosystems, South Africa has released thousands of weewil insects to combat the spread of Salvinia minima, an invasive aquatic plant threatening the Hartbeespoort Dam.
The Department of Water and Sanitation, in collaboration with the Centre for Biological Control, introduced the Cyrtobagous salviniae weevil, a biological control agent known for effectively targeting invasive plant species.
Deputy Minister Sello Seitlholo, who supervised the release, explained that the invasive weed depletes oxygen levels in the water, leading to fish deaths earlier this year. The weevils, which are subaquatic herbivores, specifically feed on Salvinia minima, helping to restore the dam’s ecological balance.
Salvinia minima, native to South America, was first identified in the Hartbeespoort Dam in 2011 and has since spread to other water bodies in the North West and Gauteng provinces, even reaching the Limpopo River near the Botswana border.
Experts from the Centre for Biological Control will monitor the weevils’ progress to assess their impact on the invasive plant population.