none Entered To evaluate direct potential influence of the insect pathogenic bacterium Empedobacter brevis GXW15-4 on parasitoid Metrorus pulchricornis, laboratory trials were conducted to examine impacts of the bacterial solution on adult eclosion, fecundity and longevity. Parasitoid pupal cocoons aged 1 and 3 days were immersed in bacterial solutions at 1.25 X 107 cfu/mL or 5.00 X 107 cfu/mL for a short time, with those immersed in water as control, and then were observed for adult emergence and reproduction. There were no interactive effects between bacteral concerntration and parasitoid pupal age on adult eclosion, fecundity and longevity of emerged adults. Pupal age showed no significant influence on wasp fecundity and longevity, while bacterial concentration had significant effects on fecundity and longevity of wasps. Wasp fecundity and longevity decreased under the high bacterial concentration in comparison with those at the low bacterial concentration and water control, but did not 'differ between later two treatments. To examine direct impacts of the bacteria on adult parasitoids, sugar solutions with bacteria were fed to wasps. Toxic responses were detected in wasps fed solutions with a recommended or higher concentration of bacteria, wasp death appeared 48 h post feeding and mortality reached over 50% at 96 h post feeding. Another feeding trial was conducted to test the combined impacts of low bacterial concentrations (1.25 X 107 and 3.13 X 106 cfu/mL) and feeding frequency on adult longevity. Bacterial concentration and feeding frequency interacted in their impacts on adult longevity. Adult longevity was not affected by feeding frequency under the higher conceutration tested, but increased with increasing feeding frequency under the lower bacterial concentration and water treatments. The results suggest that E. brevis could be nontoxic to M pulchricornis when applied at below the recommended concentration. Oct 2014