This study was conducted to determine the effect of the fungusZoophthora phytonomi(Arthur) on rates of parasitism byBathyplectes anurus(Thomson) andB. curculionis(Thomson). TheseBathyplectesspecies parasitized an average of 38.6 ± 1.96 and 14.0 ± 2.21% of the alfalfa weevils,Hypera postica(Gyllenhal), dissected during 1989 and 1990, respectively. However,B. curculionisparasitized only 0.15% of the 3,200 alfalfa weevil larvae reared during this study. Peak host density coincided with peak rates of parasitism byB. anurusfor reared larvae and occurred ≈3 d before the peak rate of parasitism for dissected larvae. Peak incidence of parasitism for both reared and dissected larvae occurred ≈6 d before the peak in the epizootic ofZ. phytonomi. Z. phytonomiindirectly caused high mortality ofB. anurusafter peak rates of parasitism and peak host density during 1989.B. anurusand the fungal pathogen have coexisted for 10 yr in central Kentucky with no apparent long-term reduction ofB. anurus.