Munch, munch, much – beetle makes meal out of pesky river plant

The Friends of the Liesbeek #DreamTeam, from left, are Barbara Everts, Zanele Mthanganya, Mncekeleli Klaas, Tanduxolo Gusha, Anele Mpambani, Sivuyile Michale and, crouching, Mlungiseleli Mbikwana.

A South American beetle has been enlisted to combat an invasive water weed choking the Liesbeek River.

The tiny beetle makes a meal out of the pesky weed, Parrot’s Feather, AKA myriophyllum aquaticum.

Late last month, the Friends of the Liesbeek’s (FOL) #DreamTeam visited the facility in Westlake where the City of Cape Town’s invasive-species unit is rearing the beetle and other helpful biological control agents.

The Liesbeek team spent the morning collecting both larvae and adult specimens of the Lysathia species of beetle, which comes from the same part of the world as the Parrot’s Feather, according to FOL manager Phil McLean.

The beetle was an able nemesis for a weed that was otherwise invasive in South Africa because it had no natural enemies here, he said.

Several large infestations of the Parrot’s Feather have the Observatory-end of the Liesbeek in a stranglehold. “The weed chokes the river, cutting down on habitat for wildlife like fish and causing the river to silt up,” said Mr McLean.

Last Friday afternoon, the #DreamTeam took turns releasing the beetles and their larvae into patches of their host plant.

“Here we hope they will enjoy the conditions enough to multiply and spread to other patches, thus eating our problem away,” said Mr McLean.

The #DreamTeam had learnt a great deal about plant invasions and the role of biological control agents in helping to combat them, he said.

“These agents are not a panacea, and Parrot’s Feather still requires human intervention to keep its numbers and impacts to a minimum, but it certainly helps to make the job a little more manageable,” said Mr McLean.