none Studies were carried out on host age preference, developmental period and longevity of Microplitis manilae (Ashmead) a larval parasitoid of Spodoptera species imported from Thailand. Experiments conducted with 4 larval age groups of the fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith), revealed that age groups 1 and 2 were most suitable for the development of the endoparasitoid Microplitis manilae . The developmental period of M. manilae ranged between 13-18 days for temperatures between 23-27 degree C, 50-70% RH and 14:10 LD photoperiod. Highest parasitization was observed for M. manilae when 2 females were exposed to 20 hosts for 30 min at 26 plus or minus 1 degree C. Adult longevity of males and females was approximately 6 days at 26 plus or minus 1 degree C. This biological information will be used for rearing this parasitoid for additional laboratory studies or in the event M. manilae is considered for inundative or inoculative releases.