Biology of Plassey Borer, Chilo Tumidicostalis (Hampson) (Crambidae: Lepidoptera)

Abstract

Biological studies of Chilo tumidicostalisHampson (Crambidae; Lepidoptera) revealed that the female lays eggs in 3-4 batches which averaged 410.64±45.21 eggs per female. The incubation period of the eggs was 7.05±0.60 days with hatching percentage as 97.56±0.90 %. There was a total of 5 larval instars and the duration of first, second, third, fourth and fifth larval instars were 3.20±0.52, 3.7±0.47, 4.75±0.79, 6.05±0.69 and 6.35±0.67 days, respectively. The pupa and adult showed sexual dimorphism and variation in duration of pupal and adult period. The length of the male and female pupa was 26.78±0.10 and 32.85±0.07 mm, respectively. The length of the adult male and female was 11.62±0.15 and 12.74±0.24 mm, respectively. The width of the adult male and female was 24.31±0.63 and 28.73±0.78 mm, respectively. The average pupal period of male and female was 7.25±1.21 and 8.1±1.37 days, respectively. Also, the adult male and female longevity was 3.9±0.64 and 4.8±0.77 days, respectively. The sex ratio was found to be 1:1.24 (male:female).