Discovery and Bioassay of a Kairomone from Waterhyyacinth, Eichhornia Crassipes

  • Ernest S. Del Fosse
  • B. David Perkins


Adult mottled waterhyacinth weevils, Neochetina eichhorniae Warner (Coleoptera: Curculionidae), were tested in an olfactometer and in 1-liter jars for their response to a chemical (or complex of chemicals) produced by young, growing tissue of waterhyacinth, Eichhornia crassipes [Mart.] Solm-Laubach. A significant number (P=< 0.001) were attracted to this chemical, which is properly termed a kairomone. Significantly high overstory (P =< 0.05) and feeding (P =< 0.001) also occurred on waterhyacinth tissue with the higher levels of the kairomone. This kairomone apparently concentrates waterhyacinth weevils (both N. eichhorniae and N. bruchi Hustach) and waterhyacinth mites, Orthogalumna terebrantis Wallwork (Acari: Galumnidae), around fresh arthropod feeding on waterhyacinth. Part of the chemical complex apparently is used as a phagostimulant and oviposition stimulant for Neochetina spp.
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