Biology of Spodoptera litura Fabricius on cabbage

Abstract

The investigations on biology were carried out in the laboratory of Department of Entomology, C. P. College of Agriculture, S.D. Agricultural University, Sardarkrushinagar during 2013-14. An average length and breadth of eggs measured to be 0.58 + 0.02 mm and 0.49 + 0.02 mm, respectively. An average hatching percentage and incubation period were 93.16 ± 4.33 per cent and 3.48 + 0.77days, respectively. The larva of S. litura passed through six larval instars. The average length of the first, second, third, fourth, fifth and sixth instar larva was 1.48 + 0.11, 3.78 + 0.10, 10.52 + 0.33, 18.75 + 0.61, 26.30 + 0.81 and 35.32 + 0.87 mm, respectively, while the average breadth of the first, second, third, fourth, fifth and sixth instar larva was 0.32 + 0.04, 0.72 + 0.06, 1.38 + 0.10, 2.19 + 0.10, 2.96 + 0.15 and 4.24 + 0.17 mm, respectively. The length and breadth of pre-pupa measured to be27.65 + 1.35 and 3.91 + 0.18 mm, respectively. Male pupal length and breadth were 19.20 + 0.93 and 6.01 + 0.36 mm, respectively. While, female pupal length and width measured to be19.39 + 0.93 and 6.28 + 0.45 mm, respectively. The average developmental period of first, second, third, fourth, fifth and sixth instars larva was 3.20 + 0.41, 2.96 + 0.73, 3.36 + 0.64, 3.04 + 0.79, 3.28 + 0.46 and 2.76 ± 0.44 days, respectively with a total larval period of 17.88 + 1.51 days. An average developmental period of pre-pupa was 1.56 + 0.51 days. An average developmental period of male and female pupa was 8.24 + 0.93 and 9.52 ± 0.96 days, respectively. An average length and breadth of adult male measured as19.46 + 0.98 mm and 38.34 ± 0.76 mm, respectively while, in case of female it measured to be19.61 + 1.03 mm and 38.77 ± 0.70 mm, respectively. An average pre-oviposition, oviposition and post-oviposition period were 1.52 + 0.51, 7.72 + 1.37 and 1.48 + 0.71 days, respectively. An average longevity of male and female were 8.32 + 1.31 and 10.36 + 1.25 days, respectively and total life period of male and female were 36.28 ± 2.32 and 38.24 ± 2.52 days, respectively. The fecundity of female recorded as 2267.92 ± 175.97eggs. Sex ratio of male: female was recorded as 1: 1.25.