Four manure treatments were utilized in an experimental caged layer house. One excluded soldier flies,Hermetia illucens(L.), and other dipterous larvae chemically; one was a check; one initially favored the soldier fly with a single addition of 2.5 cm water; and one allowed periodic development of house fly,Musca domesticaL., and lesser house fly,Fannia canicularis(L.), larvae by monthly removal of all manure and soldier fly larvae. Soldier fly larvae were demonstrated to cause significant reductions in house fly and lesser house fly populations and manure moisture. Manure accumulation was also reduced.