Study on Biology of Fall Armyworm, Spodoptera frugiperda (J.E. Smith) on Maize, Zea mays L. in Manipur, India

Aim: To study the biology and morphometric parameters of different stages of fall armyworm, Spodoptera frugiperda.

Study Design: Experimental study.

Place and Duration of Study: PG laboratory, Department of Entomology, College of Agriculture, Iroisemba, CAU (Central Agricultural University), Imphal, June-August 2022.

Methodology: The egg masses collected from maize fields were transferred to sterilized petri plates containing maize leaves and reared under laboratory conditions (25±2°C, 70±10% RH). Duration and morphometric parameters of different stages of fall armyworm were recorded regularly.

Results: The mean incubation period of eggs was observed to be 1.90 days. The larval period of six instars were recorded to be 2-4, 2-5, 2-3, 2-3, 2-3, 2-3 and 3-6 days, respectively. The mean larval length of six instars were 1.91, 3.38, 6.15, 9.78, 18.60 and 32.30 mm, respectively. The mean larval width of six instars were 0.33, 0.74, 1.31, 2.26, 2.92 and 3.53 mm, respectively. The average larval weight of six instars were 0.0031, 0.0214, 0.0420, 0.0503, 0.0576 and 0.0652 gm, respectively. The total larval duration was observed to be 16.70 days. The male and female pupal period was found to be 7.60 and 7.10 days, respectively. The average male pupal length, width and weight were 14.79±0.18 mm, 4.54±0.14 mm and 0.17±0.01 gm, respectively. The average female pupal length, width and weight were 13.0-18.20 mm, 4.0-5.2 mm and 0.18±0.01 gm, respectively. The ovipositional period was found to be 1-6 days. Mean longevity of males and females were observed to be 8.70 and 9.00 days, respectively. The total life cycle of male and female lasted 34.90 and 35.60 days, respectively.

Conclusion: This study clearly provides basic information about the biology of this recently invaded pest. To prevent the potential devastating occurrence, compatible integrated pest management strategies are needed at the early stages of FAW infestation.