Integrated control of water hyacinth in peri-urban environments, linking science to society

SOSA, ALEJANDRO J.; RIGHETTI, TOMÁS; GUALA, MARIEL E.; FALTLHAUSER, ANA C.; MC KAY, FERNANDO; CABRERA WALSH, GUILLERMO; HERNÁNDEZ, M. CRISTINA; HILL, MARTIN

Engelberg

Simposio; XV International Symposium on Biological Control of Weeds; 2018

CABI

Water hyacinth (Eichhornia crassipes [Mart.] Solms) is one of the worst aquatic weeds worldwide. In Argentina, in spite of being in its native range, there are two registered cases of invasion outside its natural distribution area. In the first one, in the dam “Los Sauces” of La Rioja province, a biological control program was successfully implemented using the weevil Neochetina bruchi Hustache. This was one of the first cases where biological control was used against this weed in the world. Secondly, an invasion of E. crassipes was recorded in Laguna del Ojo, San Vicente, Buenos Aires province. There, the weed coverage went from 1–2 ha to more than 25 ha in two years, affecting the navigability, fishing and weekend tourism, which are activities of great importance for the local community due to its proximity to Buenos Aires city. The objective of this work was to conduct an integrated biological and mechanical control plan for this aquatic weed, in collaboration with social and political stakeholders that make use of the lake. In the short period from 2015 to 2017, the positive effects of this management strategy began to be evident. This was reflected in the decrease of biomass and volume of E. crassipes by approximately 60%. The control was coupled with the removal of plants mechanically, clearing the water body almost entirely. By initially using biological control, there is an assumed economic saving of 40–60% for the municipality. Currently, periodic monitoring is maintained, and an interaction with the local community has been established. An agreement has been made with schools, through the government's department of education, to carry out mass-rearing of the insects Megamelus scutellaris Berg and N. bruchi, with active participation of the students, for subsequent releases in the lake. This is the first weed biological control work in South America which actively integrates a local community.