Hyacinth cover down to 19%… and it is not the hyacinth bug biting you

Water hyacinth cover is down to 19% on the Hartbeespoort Dam, proving that the biological control is working,” the Centre for Biological Control (CBC) at Rhodes University said last week.


This is the third year that biological agents in the form of hyacinth-specific insects, are used to address the hyacinth problem.

The CBC team visited the dam last week to assess progress and said the Megamelus and the Neochetina weevils are working well to damage the plants. The plants are noticeably brown and sad-looking.

Regarding the swarms of insects plaguing residents at night, the team said 90% of these insects are midges/miggies. “These insects explode in warmer months, and in response to poor water quality. They can survive as larvae in polluted water because they have high levels of haemoglobin which makes them red. Their common name is bloodworm. The haemoglobin allows them to take up the small amount of available oxygen in the water.”

“The water hyacint insect, Megamelus does not bite! Miggies bite and are called biting midges.
Please acknowledge the hard work that the biocontrol agents are doing for Hartbeespoort.”