The bioinsecticidal activity of organic extracts of Tagetes erecta L. (Asteraceae) was evaluated on neonate larvae of Spodoptera frugiperda J. E. Smith (Lepidoptera: Noctuidae) a major maize pest in the world. The acetone leaf extract (500 ppm) of T. erecta induced an antifeedant effect, causing a 50% reduction of larval weight in comparison with the control. Larval weights were drastically reduced at 7 d, but even more so at 14 d, when T. erecta extracts also caused substantial mortality. Three leaf extracts of T. erecta caused high larval mortality, with hexane (48%), acetone (60%) and ethanol (72%). Further T. erecta leaf extracts caused pupal mortalities of 40–80%. The use of such plant extracts can be proposed as bioinsecticides to control S. frugiperda, in a more environment-friendly manner.