Fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith), is an economically important insect pest of maize in most African countries, including Ghana. Hence, this study tested the efficacy of selected biorational and synthetic insecticides for the control of FAW in two maize cultivars in Ghana. The cultivars, Ewul-boyu and Wang-dataa, and the insecticides, neem seed oil (NSO) (azadirachtin), Agoo (Bacillus thuringiensis, Bt + Monosultap), KD 215 EC (Chlorpyrifos + Lambda-cyhalothrin) and K-Optimal (Lambda-cyhalothrin + Acetamiprid), were arranged in split-plots design. Data were collected on FAW larval infestations, damage and yield. Cultivars had no significant effect on the variables measured. Mean larval infestation before treatments application were not significantly different (P > 0.05) among the insecticides tested. After treatments application, infestation was highest in the untreated control and lowest in maize treated with K-Optimal. Damage levels (following Davis scale) in the untreated control (5.3) was significantly higher than in the insecticide treatments (3.0–3.6). Yields were at least 1.7-fold higher in all insecticide treatments than in the untreated control in both years. The benefit-cost (BC) ratios showed that farmers who do not protect their maize (untreated control) can break even. However, using either biorational or synthetic insecticides resulted in between 1.5 and 2.0-fold returns on investment with Agoo having the highest. In conclusion, the maize cultivars tested are not resistant to FAW. Therefore, farmers should use environmentally safe insecticides (e.g., NSO or Bt) to mitigate FAW damage since their efficacy and economic returns are not different from those of synthetic origins.

中文翻译：

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栽培品种和杀虫处理对秋粘虫、草地贪夜蛾（JE smith）、玉米侵染和危害的影响

秋粘虫 (FAW) 草地夜蛾 (JE Smith) 是包括加纳在内的大多数非洲国家的玉米重要经济害虫。因此，本研究在加纳的两个玉米品种中测试了选定的生物理性和合成杀虫剂控制秋粘虫的功效。品种 Ewul-boyu 和 Wang-dataa，以及杀虫剂印楝籽油 (NSO)（印楝素）、Agoo（苏云金芽孢杆菌，Bt + Monosultap）、KD 215 EC（毒死蜱 + 高效氯氟氰菊酯）和 K-Optimal（ λ-三氯氟氰菊酯 + 啶虫脒），以裂区设计排列。收集有关秋粘虫幼虫侵染、损害和产量的数据。品种对测量的变量没有显着影响。在测试的杀虫剂之间，处理应用前的平均幼虫侵染没有显着差异（P > 0.05）。施用处理后，未处理对照的侵染率最高，而用 K-Optimal 处理的玉米侵染率最低。未处理对照 (5.3) 中的损伤水平（遵循戴维斯量表）显着高于杀虫剂处理 (3.0-3.6)。在这两年中，所有杀虫剂处理的产量都比未处理的对照高至少 1.7 倍。收益成本 (BC) 比率表明，不保护玉米（未经处理的对照）的农民可以收支平衡。然而，使用生物合理或合成杀虫剂会产生 1.5 到 2.0 倍的投资回报，其中 Agoo 最高。总之，所测试的玉米品种不抗秋粘虫。因此，农民应使用环境安全的杀虫剂（例如，