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Title: Feeding impact of the planthopper taosa longula on waterhyacinth Eichhornia crassipes

Author
item CABRERA WALSH, GUILLERMO - South American Biological Control Lab(SABCL)
item SACCO, JOAQUIN - Laboratorios Fox
item HERNANDEZ, M.CRISTINA - South American Biological Control Lab(SABCL)
item SOSA, ALEJANDRO - South American Biological Control Lab(SABCL)
item CARDO, M. VICTORIA - Universidad De Buenos Aires
item ELSESSER, GERARDO - Maimonides University

Submitted to: BioControl
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/29/2012
Publication Date: 12/20/2012
Citation: Cabrera Walsh, G., Sacco, J., Hernandez, M., Sosa, A., Cardo, M., Elsesser, G. 2012. Feeding impact of the planthopper taosa longula on waterhyacinth Eichhornia crassipes. Biocontrol. Vol 23, No. 2, 160-169. http://dx.doi.org/10.1080/09583157.2012.745483

Interpretive Summary: Taosa longula is a planthopper from South America that is a candidate for the biological control of waterhyacinth, which is a serious weed around the world. Like all planthoppers, this insect sucks plant juices, thus depriving the plant of its nourishment, and causing growth stunting and decay symptoms. The damage that T. longula causes to the clonal reproduction, biomass production, and growth of waterhyacinth was studied through a paired greenhouse trial with floating cages (one treated and one control per pool). The performance of the plant, starting from two plants per treatment, was evaluated at different insect densities, 5, 10, 15 and 20 per cage. The tests showed that feeding by more than 5 insects per cage reduced waterhyacinth growth and biomass. An index based on the difference in the canopy growth between each treatment/control pair suggested that intraspecific competition may have occurred at densities above 10 nymphs per cage. These results suggested that this planthopper could be an effective agent for the biological control of waterhyacinth.

Technical Abstract: Taosa longula Remes Lenicov (Hemiptera: Dictyopharidae), a planthopper native to South America, is a candidate for the biological control of waterhyacinth, Eichhornia crassipes (Mart.) Solms-Laubach (Pontederiaceae), a serious weed around the world. The damage that T. longula causes to the clonal reproduction, biomass production, and growth of waterhyacinth was studied through a paired greenhouse trial with floating cages (one treated and one control per pool). The performance of the plant, starting from two plants per treatment, was evaluated at different insect densities (5, 10, 15 and 20 nymphs per cage) until all the nymphs molted to adults. The tests showed that feeding by more than 5 nymphs per cage reduced waterhyacinth growth and biomass. Clonal reproduction was inhibited only when the number of nymphs exceeded 15 per cage. An index based on the difference in the slopes of canopy growth between each treatment/control pair suggested that intraspecific competition may have occurred at densities above 10 nymphs per cage. These results suggested that this planthopper could be an effective agent for the biological control of waterhyacinth.