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.