|Hernandez, M.CRISTINA -|
|Sacco, Joaquin -|
|Cabrera Walsh, Guillermo -|
Submitted to: Biocontrol Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 6, 2011
Publication Date: August 30, 2011
Citation: Hernandez, M., Sacco, J., Cabrera Walsh, G. 2011. Biology and host preference of the planthopper Taosa longula (Hemiptera: Dictyopharidae) a candidate for biological control of water hyacinth. Biocontrol Science and Technology. 21(9):1079-1090. Interpretive Summary: A promising planthopper, Taosa longula, was found during explorations throughout northern Argentina, South America, in search of natural enemies of the worldwide weed water hyacinth; this aquatic weed invaded the southern States in USA and produced serious problems in canals and lakes. As part of the evaluation tests of this new species as a candidate for biocontrol of water hyacinth, the biology and development time related to temperature were studied, as well as the specificity of this species to water hyacinth and other related species. Specificity testing was developed in three stages: a no-choice feeding test on cut leaves in rearing chambers, a no-choice test in a greenhouse on whole plants, and a double-choice test on whole plants, also in a greenhouse. Taosa longula showed a clear preference for water hyacinth and exhibited warm climate requirements, making it an attractive candidate for biological control of water hyacinth in tropical and subtropical areas.
Technical Abstract: Taosa longula Remes Lenicov (Hemiptera: Dictyopharidae) is a planthopper from the South American tropics that feeds on water hyacinth, Eichhornia crassipes (Mart.) Solms-Laubach (Pontederiaceae). The biology of T. longula was studied in the laboratory and field to evaluate it as a potential biological control agent for this widespread aquatic weed. The developmental time of nymphs was recorded at different temperatures (15, 19, 23, 25, 27 and 30ºC), and developmental threshold temperatures were obtained for the different instars. The host range was evaluated in terms of development and feeding preference. Development from instar I to adult was recorded in two no-choice trials, one with cut leaves of Pontederiaceae, and a second with growing whole plants. In the cut-leaf tests, adults were obtained from Pontederia. Cordata var. cordata, P. rotundifolia and water hyacinth. In the whole plant test, T. longula adults were obtained only from water hyacinth. Feeding preference was evaluated by means of a paired choice test with 10 T. longula first instars on whole plants of P. c. cordata, P. rotundifolia and water hyacinth. The number of insects that fed on water hyacinth was significantly higher than on P. c. cordata and P. rotundifolia. Taosa longula showed a clear preference for water hyacinth and exhibited warm climate requirements, making it an attractive candidate for water hyacinth biological control in tropical and subtropical areas.