On-farm evaluation of integrated management strategies for fall armyworm (Spodoptera frugiperda) in maize across Kenya and Ghana

Fall armyworm (FAW), Spodoptera frugiperda, is one of the most destructive pests of maize worldwide. Since invading Africa in 2016 and China in 2019, it has caused substantial crop losses, especially across sub-Saharan Africa. To identify practical, smallholder-friendly pest management tactics, the FAO–China South–South Cooperation FAW Project conducted on-farm trials at two sites in Kenya (Bungoma and Embu) and two in Ghana (Kpong and Pampaso). Baseline surveys revealed infestation rates of 73.3–93.7%, with larval densities of 95–532 larvae per 100 plants. Six treatments were compared against an untreated control: neem oil, Bacillus thuringiensis (Bt), emamectin benzoate and chlorantraniliprole (Kenya) or lambda-cyhalothrin (Ghana), each applied either as a knapsack-spray or as sand granules dropped into the maize whorl. Leaf damage levels and number of living larvae per plant were recorded weekly. After one season, emamectin benzoate both sprayed and sand-applied consistently provided the lowest leaf damage level ((1.06±0.02)–(1.35±0.07)) compared with the control ((3.21±0.16)–(4.60±0.16)) in Kpone and Pampaso of Ghana. In Kenya, emamectin benzoate also resulted in lower leaf damage levels ((1.21±0.03)–(3.17±0.09)) compared with the control ((4.48±0.05)–(6.30±0.18)) at Embu and Bungoma. Bt with sand treatment was highly effective in Ghana ((1.20±0.04)–(1.29±0.07)) but performed less well in Kenya ((3.98±0.08)–(6.97±0.16)). Neem oil provided moderate suppression with leaf damage levels ((1.31±0.06)–(2.04±0.12)) in Ghana and ((3.13±0.08)–(3.58±0.16)) in Kenya, whereas lambda-cyhalothrin failed completely. In parallel, we screened five Ghanaian and eleven Kenyan local maize varieties for natural resistance; the Omankwa variety showed significantly lower leaf damage level ((1.91±0.12)–(2.73±0.21)) than the Lake (hybrid) variety ((2.78±0.31)–(3.93±0.17)) in Ghana; in Kenya, Pioneer (2.52±0.12), SC Tembo 73 (2.58±0.14) and WH508 (2.44±0.11) showed significantly lower leaf damage levels in Bungoma compared with DK777 (5.44±0.08), W301 (5.47±0.07), Tembo (Seedco) (5.71±0.07), and Sungura (Seedco) (3.76±0.07) in Embu. These trials offer smallholder farmers direct, comparative evidence to support cost-effective and locally adapted FAW management decisions.