Evaluations of Neem (Azadirachta indica) Extracts for the Management of Fall Armyworm (Spodoptera frugiperda) in Maize

Abstract

The fall armyworm (Spodoptera frugiperda, FAW) threatens global maize output. Synthetic pesticides are linked to pest resistance and environmental damage, making sustainable alternatives necessary. This study tested neem (Azadirachta indica) extracts at six concentrations T1: 10 mL bio-extract + 20 mg plant material + 90 mL D.H₂O, T2: 8 mL bio-extract + 40 mg plant material + 92 mL D.H₂O, T3: 6 mL bio-extract + 60 mg plant material + 94 mL D.H₂O, T4: 4 mL bio-extract + 80 mg plant material + 96 mL D.H₂O, T5: 2 mL bio-extract + 100 mg plant material + 98 mL D.H₂O, T6: control, effectively controlled fall armyworm (FAW) in lab and field settings. Our investigation showed that larvae were most susceptible, and mortality increased dose-dependently. Larval mortality ranged from 13.36% to 31.32% at low values (T1–T2) to >80% at higher concentrations (3–5%). At 5% concentration, pupae mortality peaked at 15.14. All therapies had low adult mortality, 6.67%. Statistical analysis showed significant treatment differences (p < 0.001). The FAW mortality rate correlated most with grain yield (r = 0.927), indicating that larval suppression directly boosted productivity. High correlations (r > 0.80 across all traits) show that neem-mediated FAW inhibition reduced insect pressure and promoted vegetative growth, increasing cob output and grain yield. These findings underscore neem extracts as an effective, eco-friendly alternative to synthetic insecticides. Integrating neem into pest management programs could enhance sustainable maize production, though long-term ecological impacts and resistance development warrant further study.