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ThesisItem Open Access Biology, population dynamics and management of fall armyworm, Spodoptera frugiperda (J.E. Smith) on maize(CCSHAU, Hisar, 2021-09) Deepak Kumar; Maha SinghThe present investigation entitled, “Biology, population dynamics and management of fall armyworm, Spodoptera frugiperda (J.E. Smith) on maize” was carried out at Research Farm and laboratories, Department of Entomology, CCS Haryana Agricultural University, Hisar and Research Farm CCS Haryana Agricultural University Regional Research Station, Uchani, Karnal during Kharif, 2020. The biology of S. frugiperda was observed at four different temperatures viz., at room temperature, 15°C, 25°C and 35°C, respectively. The average fecundity of S. frugiperda was 1110.6, 714.8, 1303.9 and 1013.1 eggs/female at room temperature, 15°C, 25°C and 35°C, respectively. Egg hatchability was observed as 93.3, 74.9, 83.5 and 92.5 per cent whereas incubation period as 2.68, 6.08, 3.24, 2.80 days at room temperature, 15°C, 25°C and 35°C, respectively. Average larval period was 15.44, 32.97, 19.96 and 15.09 days whereas larval survival as 85.6, 58.8, 62.4 and 84.3 per cent at room temperature, 15°C, 25°C and 35°C, respectively. Pupal period was noticed as 7.78, 25.63, 9.28 and 7.42 days whereas the adult emergence as 64.2, 52.0, 63.0 and 68.5 per cent at room temperature, 15°C, 25°C and 35°C, respectively. Total life cycle of females was observed as 35.13, 79.33, 45.19 and 34.73 days while those of males as 33.24, 77.05, 42.71 and 32.46 days at room temperature, 15°C, 25°C and 35°C, respectively. Studied on population dynamics of S. frugiperda revealed that larval population prevailed from 28th SMW to 40th SMW. Its peak was observed during the 33th SMW with a mean population of 4.93 larvae per plant. The average plant infestation was observed from 28th SMW to 40th SMW (second week of July to first week of October) with a maximum of 79.1 per cent during 40th SMW. Larval population had a significant positive correlation with evening relative humidity (r = 0.652) and significant negative correlation with sun shine hours (r = -0.634) whereas per cent plant infestation indicated a non-significant correlation with all the weather entities. During the study period, three hymenopteran larval parasitoids (Chelonus sp., Cotesia sp., Campoletis sp) were also observed. Studies on screening of maize genotypes against S. frugiperda indicated that amongst the 55 maize genotypes, HM 10 recorded lowest leaf injury (4.45 score), while HKI 1348-6-2 recorded highest leaf injury (8.85 score). Five genotypes (HKI 1105, HKI 139, HKI 193-2, HKI 1011 and HM 10) were categorized as partially resistant (leaf injury score: 4.0 to 5.99), 20 genotypes as susceptible (leaf injury score: 6.0 to 7.99) and 30 genotypes as highly susceptible (leaf injury score: 8.0 to 9.00). Studies on effect of date of sowing on incidence of S. frugiperda indicated that plant infestation and larval population was observed minimum when crop was sown during last week of June while infestation and larval population gradually increased as date of sowing is delayed.
