Homozygous JhI-21^GE15185 mutant adults are more sensitive to fungal infection (B. bassiana) than wild type controls. This increase in sensitivity is seen following both natural infection and infection through septic injury. No reduction in survival is seen following wounding or in response to infection with either Gram-negative (Ecc-15) or Gram-positive (M. luteus or S. aureus) bacteria. An increased number of hemocytes are seen in JhI-21^GE15185 mutants compared to wild type, but these hemocytes are defective in the uptake of B. bassiana fungal spores. Defects are also seen in the phagocytic uptake of E. coli and S. aureus. An increased number of plasmatocytes is seen in homozygous JhI-21^GE15185 third instar larvae. The number of crystal cells is similar to wild type and, as in wild type, strong melanisation occurs in response to injury.