BIOLOGY AND MORPHOMETRICS OF THE FALL ARMYWORM, Spodoptera frugiperda J. E. SMITH (LEPIDOPTERA: NOCTUIDAE) IN IBADAN, SOUTHWEST NIGERIA

Abstract

Studies on the development and morphological description of the fall armyworm, Spodoptera frugiperda are important for its sustainable management on the continent. Such studies are, however scanty in Africa and non-existent in Nigeria. Consequently, we studied fall armyworm development on maize leaves from egg to moth. Data was collected on egg hatchability, development duration, and morphometrics of life stages. Total development duration for egg, larva, and pupa was 2–3, 11–12, and 7–10 days, respectively. Egg incubation period, diameter, and percentage hatchability were 2.10±0.06 days, 0.24±0.01 mm, and 81.50±2.28 %, respectively. Larva comprised six-instars; with the first and last respectively measuring 1.64±0.03 mm and 26.45±0.44 mm body-length, 0.18±0.01 and 3.45±0.07 mm body-width, 0.12±0.01 mm, and 2.45±0.02 mm head-capsule-width. Pupa body-length and body-width were 14.38±0.14 mm and 4.21±0.04 mm, respectively. Female moths were larger and emerged a day ahead of males. Body length, body width, and wingspan of male and female moths were 14.93±0.25 mm and 14.66±0.19 mm; 2.71±0.08 mm and 3.14±0.05 mm; and 13.65±0.24 mm and 14.17±0.14 mm, respectively. Development duration of S. frugiperda larvae in Nigeria is shorter than that reported in the Americas but within the range reported in other parts of Africa. Findings in the study also confirm the ability of S. frugiperda moths to survive without food for up to a week making them a possible contaminant of maize grains and other agricultural commodities during transcontinental trades. Information provided in this study will aid the detection, identification, and management of the pest on farmers’ field and on traded commodities.