The bugs are back on the Hartbeespoort Dam

The Centre for Biological Control (CBC) at Rhodes University once again visited the Hartbeespoort Dam last weekend to bring more of their hyacinth-eating bugs to control the hyacinth infestation this summer.

Prof Julie Coetzee and Keneilwe Sebola of the CBC.

Prof Julie Coetzee and her team delivered the Megamelus scutellaris planthopper bugs to the Harties Foundation that is currently busy with a mass-rearing project in order to continuously release the little insects on the invasive water plant.

“We work in collaboration with the Harties Foundation that has constructed a facility to propagate the bugs. We visited the dam over the weekend and delivered the insects that will be released by die foundation as the numbers grow,” she said.

“The success of the biological control of the hyacinth is fantastic. We are really pleased.”

Biological control agents in the form of plant specific bugs have been instituted on the Hartbeespoort Dam since the 1980’s but due to periodic herbicide application, their population has been inhibited.

However, biological control, in the form of weevils, was once again instituted on the dam in 2018 by the Rhodes University in conjunction with the Department of Environmental Affairs, and since no herbicides have been used since then, a mass die-off of hyacinth took place.

Currently six different kinds of insects can be found on the hyacinth but most of the success is ascribed to the planthopper that has been continuously and intensively introduced since last year. “”The two most noticeable insects are the Neochetina weevils, and the water hyacinth plant hopper, Megamelus scutellaris, which come from South America too. These insects have been thoroughly studied in South Africa, and elsewhere, including the USA and Australia, over many years to make sure that they are safe (i.e. only feed on water hyacinth) and effective in controlling water hyacinth.”