Fly to head off the weed invasion
Hydrellia agent released as SA’s first biocontrol for the Brazilian menace
The first biocontrol agent in SA invasive Brazilian waterweed was into the Nahoon River on Friday.
Representatives from various organisations, including Amathole Water and the department of environmental affairs, were in attendance.
Professor Julie Coetzee of the Centre for Disease Control (CDC), said a biological control is essentially the release of the natural predator of another species into the environment.
In this case, the “predator” being used as the biocontrol agent for the waterweed is the Hydrellia fly from Argentina.
Rhodes University PhD student Rosali Smith has been credited as the head researcher whose blood, sweat and tears culminated in Friday’s historic release.
Smith told the Daily Dispatch she and a team of researchers had been working on the fly and testing its viability in biological control for about four years.
She said that due to the species being only recently discovered, time had to be taken to learn about them and run risk assessments in quarantine. for the released
Smith explained the Hydrellia larvae are what would eat and destroy the submerged plant.
The young PhD student assured the Daily Dispatch that this new fly species would not turn its hunger onto other plants, but instead it would die out when the Brazilian waterweed did.
Smith explained that were the waterweed allowed to grow unchecked, it would eventually choke up the waterway, resulting in damaging the local ecological system and putting an end to water-based hobbies in the area, such as fishing.
Coetzee said that biocontrol is a long-term solution which is environmentally friendly but requires patience.
The species being introduced into a new environment needs time to build up and “get happy” before it heads to work.
Coetzee added that this method was a superior solution to herbacides, which would result in poisoning the rest of the ecosystem as well, and mechanical methods, which would be expensive and are not guaranteed to permanently eradicate the invasive plant species.
HANDY HELPERS: Rhodes University PhD student Rosali Smith and Ahmed Khan, of the department of environmental affairs release the first biocontrol for the Brazilian waterweed in SA into the Nahoon River.