The development of Sturmiopsis parasitica (Curran) (Diptera: Tachinidae) and levels of parasitism of its hosts, Busseola fusca Fuller, Sesamia calamistis Hampson (Lepidoptera: Noctuidae), and Chilo partellus (Swinhoe) (Lepidoptera: Crambidae), were studied. The highest rates of parasitism were 83.3 and 15% of B. fusca and C. partellus, respectively. No development occurred on S. calamistis due to maggot encapsulation. At 25 ± 0.5°C, S. parasitica larval development on nondiapausing B. fusca larvae took 14.2 d (range 10–34) and the pupal period 13.7 d for males and 15.8 d for females. Adult females that developed on C. partellus were smaller than those from B. fusca but had a similar lifespan (≈4 wk). Although first observed at 6 d after mating, maggot production peaked at 848 per female after a 12-d gestation period. Inoculation of diapausing B. fusca larvae resulted in an extended larval period of the tachinids, indicating that the seasonal carryover of S. parasitica in diapausing B. fusca larvae in Zimbabwe could be a hormone-induced physiological response. The potential of S. parasitica as a biological control agent is discussed.