Infectivity of an undescribed UruguayanNeoaplectanaspecies to the mole cricketsScapteriscus vicinusScudder andS. acletusRehn and Hebard was tested under a variety of conditions in the laboratory. At 30°C, soil moisture in the range of 5–15% had no effect on infection of the mole crickets. There was no consistent difference in infection of mole crickets exposed to nematode-infested soil for 24 h and those exposed for 72 h. There was no decline in infection of crickets for the first 7 d after introduction of nematodes into the soil at 30°C, but after 14d at that temperature, there was significant reduction in infection. Crickets exposed to nematodes at 10°C were infected significantly less often than those exposed at 30°C. Increasing nematode density from 100,000 to 1 million per m2did not increase the incidence of infection but did decrease the variability of results.