Hyacinth coverage on 4 March 2024.

The hyacinth bugs and the removal of the hyacinth seem to be winning the war on the hyacinth. Hyacinth coverage on the Hartbeespoort Dam is currently only about 15%.
“This is so exciting for us! And the Megamelus counts are more than 6000 per m2,” said Professor Julie Coetzee of Rhodes University’s Centre for Biological Control (CBC).
Rapid browning of the hyacinth plants can be seen and no plants have been left untouched by the plant hopper. The bugs will soon leave the hyacinth and will be attracted to lights.
“The planthoppers eating the hyacinth are starting to leave the plants which indicates that there is not much nutrition left. The plants are turning brown. These insects are dispersing away from the damaged plants to find new water hyacinth that are more nutritious. However, they are attracted to lights that interfere with their navigation ability. The insects are host-specific and cannot complete their life cycles on plants other than water hyacinth. They will not damage garden ornamentals or vegetables. However, they may attempt to feed on other plants to get moisture before they fly. This behaviour is purely investigative, and the insects will not survive on other plants. Furthermore, the insects are herbivores and cannot bite. They do not have biting mouthparts. Any reports of bites are from other insects like mosquitoes or biting flies that breed opportunistically in the water hyacinth mats,” Professor Julie Coetzee of the CBC said.
“Bear with us, they won’t stay around for long.”
Hyacinth currently covers approximately 276ha of the dam and Hya Matla is removing an estimated 1.6ha daily.
In the meantime, Moleaer Nanobubble technology was implemented at the Ifafi Aquatic Club in February in an effort to restore healthy biology to the ecosystem. According to Blue Planet which steers the project, the nanobubbles will soften the compacted sludge and solubilise it. The process is also supposed to remove the nutrients that hyacinth flourish from.
John Wesson of the Wildlife & Environment Society of South Africa (WESSA) said at the current rate of removing 1.6 ha of hyacinth a day, it will take 173 days to remove it all. “The problem is that due to the bugs, there is very little growth and it will reach a stage towards the end of the month that it will start sinking. Wind and rain will more than likely accelerate the process. The ideal would be to up the removal rate to get as much as possible off the water surface to have minimum sinking and adding to the already extensive sludge layer just below the surface.”