Students in the 2-year diploma course in crop protection at the CILLS (French acronym for “Permanent Interstate Committee for Drought Control in the Sahel”) Crop Protection Training Centre (Département de Formation en Protection des Végétaux) in Niger undertake laboratory or field research work on specific subjects under the supervision of resident lecturers. It is in this context that studies on the biology of the rice armyworm, Mythimna loreyi, were conducted in the laboratory on two host plants, maize and sorghum. The studies were conducted at a mean temperature of 27.01°C and mean r.h. of 41.65%. The egg-laying habits of the insect and parameters such as the length of the preovipositional period, larval and pupal developmental period and longevity of adults were studied. Larval developmental time was significantly shorter on maize than on sorghum, but there was no significant difference in the length of the pupal period. The preovipositional period ranged from 1 to 8 days with a mean of 4.32 days. There was no significant difference between the longevity of adult males and females.
