Weevils to the rescue in Banana Beach water lettuce saga
The team removed between 40 and 50 tons of water lettuce from the river.
A thousand tiny weevils were recently released to feed on the category 1 invasive alien water lettuce which has clogged the Ikotshwana River in Banana Beach.
ALSO READ : Banana Beach river choked by weed
At a meeting called by Ugu District Municipality on November 20, it was agreed that the water lettuce from the old railway bridge to the beach had to be removed, and the beach area fenced off with danger tape and signage.
The concern was that as the beach is a popular one, and the water lettuce looks like a grass ‘carpet’, someone could perhaps have mistakenly attempted to walk on it.
Alex Skene, chairman of the Umtentweni Conservancy and his team were tasked to remove the lettuce, and also cordoned off a section of the river mouth using bamboo.
Alex said they had removed between 40 and 50 tons of the plant.
Mr Skene praised Noloyisa Walingo, Ugu District Municipality’s manager of environmental management for her commitment to sorting out the problem.
“Working with Ms Walingo has been an absolute pleasure.”
Meanwhile, the department of environmental affairs had also released 2 000 biological control weevils in November, and signs of their effectiveness are already apparent.
The weevil is about 1.8mm long. An adult weevil will make small holes into and through the leaves which their larvae will then tunnel into.
This feeding and tunneling allow water to enter the air-filled cells of the plant, which leads to waterlogging and sinking of the plants.
Why has water lettuce in the Ikotshwana River been a long-standing problem?
A water sample taken on December 20 revealed 3100 e.coli per 100ml. A subsequent test on December 22 showed 6400 e.coli per 100ml, and the third test on January 7 showed 19600 e.coli per 100ml.
The water lettuce thrives in water with a high nutrient content which comes from sewage or fertiliser seepage, for example.
In Mr Skene’s opinion, the short term solution to this problem would be to repair or upgrade the wastewater treatment plant.
An inspection of the plant revealed that it is structurally sound but has had major breakdowns due to lack of proper maintenance.
June Myers, chairman of Bendigo Residents’ and Ratepayers’ Association thanked holidaymaker, Lucinda Beukes for organising the weevils from Rhodes University.
Lucinda, who lives in Mpumalanga was so concerned about the river she phoned around and arranged for the weevils to be posted to the coast.
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