Host Suitability of Maize Genotypes to Oriental Armyworm Mythimna separata (Lepidoptera: Noctuidae): Insights from Nutritional Indices and Larval Development

The Oriental armyworm, Mythimna separata (Walker), is a major maize pest, causing substantial damage and yield loss. Evaluating its nutritional and larval developmental performance on different maize genotypes is essential for identifying resistant cultivars. Eighteen maize genotypes were evaluated for host suitability to Mythimna separata larvae based on nutritional indices and larval developmental performance under laboratory conditions (25 ± 1 ° C, 50 ± 5% RH, 12:12 L:D photoperiod). Among fourth instar larvae, the highest Efficiency of Conversion of Ingested (ECI) (94.22 ± 1.99%) and Digested (ECD) food (78.81 ± 0.57%) was exhibited on CML-139. In contrast, the highest Consumption Index (CI) (3.28 ± 0.28) and Approximate Digestibility (AD) (82.35 ± 3.82) were observed on CML-208-BBB. Among fifth instar larvae, a similar trend was seen in which CML-139 exhibited the highest ECI (95.57 ± 2.22%) and ECD (98.89 ± 0.80%), respectively. The overall larval Growth Rate (GR) was highest on CML-139 (0.94 ± 0.012 mg/mg/day) and lowest on CML-208-BBB (0.09 ± 0.006 mg/mg/day). Regarding various developmental parameters, larvae reared on CML-128 had the shortest larval (12.00 ± 0.57 days) and pupal period (8.66 ± 0.33 days), while the longest durations were on NGB-17096‑1 (21.33 ± 0.88 and 11.00 ± 0.00 days), respectively. The highest adult emergence (96.69 ± 5.77%) and survival rate (86.66 ± 3.33%) were recorded in CML-139, while the lowest was in CML-556 (73.33 ± 3.33, 46.66 ± 6.66%). Larvae and pupae attained the highest weights on CML-139 (257.35 ± 0.49, 255.35 ± 0.49 mg) and the lowest on CML-208-BBB (172.49 ± 0.55, 170.49 ± 0.55 mg). Our research findings suggest that CML-139 appeared the most suitable and CML-208-BBB the least suitable among the tested genotypes. Overall, this study provides preliminary insights that may guide maize breeding programs and support the development of sustainable crop protection strategies against M. separata.