In view of the possibility of using the introduced coccinellid Cycloneda limbifer to eliminate residual aphid foci following control measures using the entomogenous fungi Entomophthora thaxteriana and Basidiobolus, experiments were carried out in the USSR on the effect of suspensions of spores of E. thaxteriana E-68 (titre up to 2.2.10⁶) and Basidiobolus 18 (titre up to 3.8.10⁵) on laboratory populations of C. limbifer. In 2 experiments, bean shoots infested with Aphis fabae were treated with E. thaxteriana E-68 or Basidiobolus 18 and larvae of C. limbifer were placed on the plants after treatment in the 1st and before it in the 2nd experiment. The predators were subsequently kept with aphid-infested bean shoots in glass cylinders. In a 3rd experiment, freshly laid eggs of C. limbifer were treated with Basidiobolus and the larvae (all of which hatched) were transferred to the glass cylinders as before. No depressive effect of the fungi was registered in terms of the duration of development or in the numbers or individual mass of the emerging adults or the fecundity of the females by comparison with controls, but the numbers of females emerging were reduced relative to the males.