The Agricultural Research Council’s (ARC’s) plant health and protection unit will, on November 25, release a leaf-feeding lady beetle called Mada Polluta in Umkhomazi, KwaZulu-Natal, to act as a biological control agent against invasive yellow bells.

ARC says yellow bells, or Tecoma stans, have become a major ecological threat in South Africa.

The plants are native to Central America but have started spreading across South Africa and neighbouring countries, forming dense stands and replacing native vegetation. It also harms the structure and function of local ecosystems.

Like other invasive alien plants, yellow bells threaten local biodiversity, ecosystems, environmental quality, food security and livelihoods in affected areas.

In South Africa, significant resources are dedicated each year to controlling invasive alien plants, with more than R8-billion having been spent between 1998 and 2020.

Many countries, including South Africa, are committed to global biodiversity goals to prevent or reduce the spread of high-priority invasive species.

The impacts of these species are further worsened by climate change, which aids the establishment and spread of both new and existing alien species, creating opportunities for naturalised plants to become invasive.

The release of the beetle, which is a collaboration project between the Department of Forestry, Fisheries and the Environment, the eThekwini municipality and Ezemvelo KwaZulu-Natal Wildlife, was approved for release in 2013, and efforts are now focused on mass rearing and releasing the beetle to help control yellow bell invasions.

In particular, the release of the beetle in Umkhomazi aims to limit the growth and spread of yellow bells in the region. More releases will occur at selected sites across the province that provide suitable habitat for the beetle.

ARC and its partners will also monitor the beetle’s establishment and effectiveness in reducing the growth, density and spread of yellow bells to ensure natural biodiversity is restored.