The change of phenoloxidase activity and number and action of hemocyte in Apriona germari larvae infected by Beauveria bassiana was investigated. The results showed that the phenoloxidase activity and the total amount of hemocyte in hemolymph of A.germari larvae infected by B.bassiana increased to maxima at 2.5 d,and were followed by a decrease. The number of granular cell and plasmatocytes showed a similar change pattern. The hemocytes of A.germari larvae resisted the invasion of B.bassiana mainly through adhesion,phagocytosis,and encapsulation. The peak response occurred around 2～2.5 d after invasion of B.bassiana. However the defense responses just temporarily inhibited the pathogen but could not clear them completely.
