City’s tiny ‘agents’ ready to tackle alien invasion
THE City is letting loose its tiniest secret agents as part of its mission to root out the environmental scourge of alien invasive plants.
More than 243 000 biocontrol insects, also known as “agents”, have since 2014 been reared for release into the environment to destroy alien invasive plants, according to Mayco member for transport and urban development Brett Herron.
The biocontrol insects project is a partnership between the Department of Environmental Affairs and Rhodes University’s Department of Entomology.
He said the project was part of the City’s plans to create jobs and managing invasive plants for a more sustainable environment.
Herron visited the City’s Invasive Species Unit’s Insect Mass Rearing Facility in Westlake yesterday.
The facility had been using an organic, cost-effective and environmentally-safe biological control method to curb alien invasive plants by breeding and releasing their natural enemies – the tiny insects – into the alien invasive plant-infested areas.
Herron said the facility currently reared agents for four aquatic alien invasive plants – namely water hyacinth, parrot’s feather, kariba weed and water lettuce – which are considered the worst invasive weeds in South Africa.
The facility also reared biocontrol agents for one terrestrial alien invasive plant: the prickly pear (Opuntia monocantha), he added.
Herron said: “Today’s visit to the insect-rearing facility has been most fascinating.
“In order to rear the agents, our team actually grows the plant which the agents are intended for.
“The aquatic invasive plants are grown in the artificial ponds at our facility and this is also where the agents grow and complete their lifecycle. The agents are then collected from these ponds when they are ready to be released on their mission.”
Each of the insects are physically counted and placed in plastic containers. Within hours they are transported and released on the specific invasive plant.
Generally, the insects are released every two weeks, while the number of insects released depends on the size of the mission field.