The bioinsecticidal activity of organic extracts of Tagetes erecta L. on L1 larvae of fall armyworm, Spodoptera frugiperda (E. Smith), was evaluated. The acetonic extract of the leaves (500 ppm) of T. erecta exhibited an antifeedant effect, causing 50% reduction in larval weight in comparison with that of the check. Information obtained on larval weight at 7 days corroborated with results obtained at 14 days when T. erecta extracts killed most larvae. The following killed the most larvae: n-hexane leaf (48%), acetone leaf (60%), and ethanol leaf, which caused most larval mortality of 72%. T. erecta leaf extracts were toxic to 40–80% of the pupae. The leaf extracts hexane, acetone, and ethanol of T. erecta killed many larvae and were evaluated at different concentrations: 125, 250, 750, and 1,000 ppm. The LC₅₀ for n-hexano leaf extract was 312.2 ppm (X² = 0.1102); for acetone leaf extract of T. erecta, 246.9 ppm (X² = 0.1598), and for ethanol leaf extract, 152.2 ppm (X² = 0.1504), with a 95% confidence. Thus, use of these extracts is suggested as a more environmentally friendly alternative to combat insect pests of maize, Zea mays L.