Life cycle and morphometrics of fall armyworm (Spodoptera frugiperda J.E. Smith) (Lepidoptera: Noctuidae) on maize crop

Authors: SHARMA, SHEELA - NEPAL AGRICULTURAL RESEARCH COUNCIL; TIWARI, SUNDAR - NEPAL AGRICULTURAL RESEARCH COUNCIL; THAPA, RESHAM BAHADUR - AGRICULTURE AND FORESTRY UNIVERSITY(AFU); NEUPANE, SARASWOTI - NATIONAL MAIZE RESEARCH PROGRAMME; Reddy, Gadi V.P.; MUNIAPPAN, P - VIRGINIA TECH

Submitted to: SAARC Journal of Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/4/2022
Publication Date: 7/20/2022
Citation: Sharma, S., Tiwari, S., Thapa, R., Neupane, S., Reddy, G.V., Muniappan, P. 2022. Life cycle and morphometrics of fall armyworm (Spodoptera frugiperda J.E. Smith) (Lepidoptera: Noctuidae) on maize crop. SAARC Journal of Agriculture. 20(1)77-86. https://doi.org/10.3329/sja.v20i1.60532.
DOI: https://doi.org/10.3329/sja.v20i1.60532

Interpretive Summary: Fall armyworm (Spodoptera frugiperda) is a polyphagous insect with host range of more than 395 plant species. Maize is the most damaging crop in the world. Biology and morphometric study of fall armyworm was conducted in Agriculture and Forestry University, Chitwan, Nepal. The average pre-oviposition, incubation, larval, pupal and average life periods was 3.75, 3, 16.31, 9.69 and 29 - days, respectively. The average length of each instar larva from I to VI instars was 1.5 mm, 3.6 mm, 7.1 mm, 11.6 mm, 18.5 mm, and 34.4 mm, respectively. The width of I to IV instars head capsule was 0.35 mm, 0.47 mm, 0.80 mm, 1.37 mm, 2.11 mm, and 2.70 mm, respectively. Pupal and adult emergence rate was 98.9% and 97.22%, respectively, with a male to female ratio of 1:1.30. Adult male was survived for 20.73 days and female was survived for 22.78 days (21-25 days) when fed with 10% honey solution. This study is useful to understand the biology and habitat of fall armyworm along with helpful to develop an integrated management protocol.

Technical Abstract: Fall armyworm (Spodoptera frugiperda) is a polyphagous a pest, native to North and South America. Fall armyworm was formally reported for the first time in January 2016 in Africa and on May 9, 2019 in Nepal. Life cycle and morphometric studies of fall armyworm (FAW) were conducted under laboratory conditions with temperature maintained at 26.04 0C and Relative humidity (RH) of 75.40 % from September to November 2020 at the Department of Entomology, Agriculture and Forestry University (AFU), Nepal. The newly emerged male and female pairs of fall armyworm adults were taken from the laboratory colony for egg laying, and freshly laid eggs were taken for the life cycle study. Gravid females laid an average of 156.25 eggs (71- 273) at a time with an average of 979.43 eggs (713-1166) during their lifetime. After egg hatching, 100 newly emerged larvae were individually reared on pieces of fresh maize leaves for this study and leaves were replaced daily. The average pre-oviposition period was 3.75 days (3-4 days), incubation period was 3 days (2-3 days), larval period was 16.31 days (14-25 days), pupal period was 9.69 days (8 – 13 days), and average life period was 29 days (26 - 32 days). The average length of each instar larva from I to VI instars was 1.5 mm (1.41-1.70 mm), 3.6 mm (3.18-3.66 mm), 7.1 mm (6.40-7.80 mm), 11.6 mm (9.40-13.50 mm), 18.5 mm (15.8-22.5 mm), and 34.4 mm (28.3-38.8 mm), respectively. The width of head capsule of each instar measured 0.35 mm, 0.47 mm, 0.80 mm, 1.37 mm, 2.11 mm, and 2.70 mm, respectively. Pupal and adult emergence rate was 98.9% and 97.22%, respectively, with a male to female ratio of 1:1.30. Larval mortality of the I, II, and III instar was 70%, 66%, and 12%, respectively, with zero mortality in the IV, V and VI instars. Adult longevity was 20.73 days (15-24 days) for male and 22.78 days (21-25 days) for female fed with 10% honey solution. This biology study can be applied for the integrated management of the fall armyworm.