INFECTIVITY OF INSECT PATHOGENS AGAINST NEOCHETINA-EICHHORNIAE, A BIOLOGICAL-CONTROL AGENT OF WATER-HYACINTH

Several insect pathogens were tested for infectivity against Neochetina eichhorniae Warner (Coleoptera:Curculionidae), a biological control agent for waterhyacinth, Eichhornia crassipes (Mart.) Solms. No mortality resulted from exposure to 21 strains of Bacillus thuringiensis. No significant mortality resulted from exposure to 2 strains of Metarhizium anisopliae. Although treatment of adult weevils with 6 strains of Beauvaria bassiana produced no significant mortality, 2 strains (BbAFA - 35%, Bb 5647 - 65%) did result in statistically significant mortality. Exposure to 2 strains of Steinernema carpocapsae resulted in 60-70% mortality. Our results indicate limited potential for these insect pathogens to control N. eichhorniae in resource recovery or wastewater treatment facilities.