Collaborative efforts to manage the cryptic invader Limnobium laevigatum in southern African water-ways.

NCUBE, JANET; COETZEE, JULIE; FALTLHAUSER, ANA C.; GRANT, MARTIN; MILLER, BENJAMIN; SOSA, ALEJANDRO J.; WEYL, PHILIP

Puerto Iguazú

Simposio; XVI International Symposium on Biological Control of Weeds; 2023

FuEDEI y CERZOS-CONICET

While the South American fresh water invader Limnobium laevigatum has been present inAfrican water ways since the early 2000’s, no management efforts have been implementedagainst the weed. Often unnoticed due to its similarity to Pontederia crassipes (waterhyacinth), L. laevigatum has spread rapidly, forming large, dense monospecific mats.Climate matching suggests large regions of Africa, including Botswana, Kenya, Malawi,South Africa, Tanzania, Zambia and Zimbabwe would be climatically suitable for invasion.Due to the high number of wind and water dispersed seeds, small seedlings and quickdownstream spread, further rapid invasion is expected - causing severe socio-economicproblems especially for rural livelihoods that depend on natural resources as well asnegatively impacting native biodiversity (especially in hotspots, Okavango and Bangweluswamps). Considering the overwhelming success of the biological control of aquaticspecies on the African continent, and an already known potential agent for the species,biological control should be considered as a management option. To this end, a consortiumhas been formed including researchers from Zimbabwe and South Africa (CBC), Argentina(FuEDEI) and Switzerland (CABI) to develop an effective biological control programme.Listronotus cinnamomeus has already been identified as potentially host specific andprioritized as a candidate agent. A population of the weevil has already been located closeto the FuEDEI laboratory in Argentina. Additional host specificity studies will commencein 2023. It is hoped that the collaborative effort will result in the successful implementationof a biological control program with the aim of reducing the current and potential negativeimpacts of this aquatic invader.