Evaluating the establishment of a new water hyacinth biological control agent in South Africa





Megamelus scutellaris, Pontederia crassipes, biological control, mass rearing, post-release evaluation, Delphacidae


Megamelus scutellaris Berg (Hemiptera: Delphacidae) is the most recent of nine biological control agents developed to manage invasive water hyacinth, Pontederia (=Eichhornia) crassipes Mart. (Pontederiaceae), in South Africa. More than a million M. scutellaris have been mass-reared and released since the first introduction of the agent into South Africa in 2013, successfully establishing overwintering populations at 32 sites in seven of the nine provinces. Establishment has also been recorded at seven of these sites through natural dispersal from sites where they had established. Inundative releases, where large numbers of M. scutellaris are released regularly, have resulted in excellent establishment, and caused a significant reduction in water hyacinth cover in areas where, historically, biological control seemed unlikely due to excessive eutrophication. Although M. scutellaris has established well throughout South Africa through classical biological control methods, this study also showed that inundative releases of biological control agents over multiple seasons results in the most effective control of the weed, especially at cool temperate and eutrophic sites.


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Miller B, Coetzee J, Hill M. Evaluating the establishment of a new water hyacinth biological control agent in South Africa. Afr. Entomol. [Internet]. 2023 Sep. 13 [cited 2023 Oct. 4];31. Available from: https://www.africanentomology.com/article/view/15613