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Biological control of floating waterhyacinth (Eichhornia crassipes) worldwide has involved the introduction of two weevils, Neochetina eichhorniae and N. bruchi (Coleoptera: Curculionidae). �In the U.S., several native plant pathogens have developed host associations with waterhyacinth, including the fungi Cercospora piaropi and Acremonium zonatum, which cause leaf necrosis. �The application of spore suspensions to weevils prior to augmentative releases could lead to additive or synergistic biological control.� Field site sampling in 2004 demonstrated a positive correlation between leaf scarring by waterhyacinth weevils and leaf coverage with symptoms of C. piaropi infection. �Ninety percent of culture plates exposed to Neochetina spp. weevils that had been sprayed with suspension containing C. piaropi or A. zonatum developed fungal colonies. �Weevils remained capable of infecting plates for two weeks after being exposed to fungal suspension. Both C. piaropi and A. zonatum were present in frass collected from weevils. �Eighty percent of waterhyacinth plants in greenhouse and field tanks that were infested with pre-inoculated weevils developed necrotic lesions caused by C. piaropi. The severity of necrosis was equal to that resulting from simultaneous infestation with non-inoculated weevils and foliar application of the fungus. �Plants in tanks receiving C. piaropi-inoculated weevils had lower numbers of leaves and reduced biomass compared to plants that received non-inoculated weevils. A. zonatum infection was enhanced on plants infested with pre-inoculated weevils compared to plants that received a foliar fungal application.� Advances in pathogen formulation and the combined use of these two plant pathogens hold promise for improving biological control of waterhyacinth.