The effects of Isaria farinosa (Holm.) and Beauveria bassiana (Balsamo) on adult stages of sunn pests Eurygaster integriceps Puton and Eurygaster austriaca (Schrk.) were investigated at 27 +/- 1 degrees C, 95% r.h. and 16L:8D in the laboratory. Two concentrations, 1x10(6) and 1x10(8) conidia ml(-1), were used. Mortality of inoculated and non-inoculated adults was counted at 6, 9 and 12 days after treatment. Beauveria bassiana caused higher mortality of both species than I. farinosa. Neither caused significantly highmortality at 1x10(6) conidia ml(-1). Both were more pathogenic at 1x10(8) conidia ml(-1) and caused more than 85% mortality 12 days post treatment. Both were more pathogenic to E. austriaca.