Homozygous CG12744^GE13306 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 Gram-negative bacteria (Ecc-15). However a fall in survival rate is seen in response to Gram-positive bacteria (M. luteus or S. aureus). The number of hemocytes in CG12744^GE13306 mutant flies is similar 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 S. aureus but not E. coli. The number of plasmatocytes in homozygous CG12744^GE13306 third instar larvae is similar to wild type. A reduced number of crystal cells is seen and less melanisation occurs following injury compared to wild type.