Biology of Helicoverpa armigera (Hubner) on tomato in South Gujarat

Biological studies of Helicoverpa armigera carried out on tomato revealed that insect eggs were hemispherical in shape and yellowish white in colour. The incubation period of insect eggs varied from 3 to 5 days indicating 53.18 per cent hatching. The neonate larva looked dirty white which turned to pink brown and pale green at maturity. The larvae passed through six instars wherein their respective durations were of 2.84 ± 0.74, 3.40 ± 0.50, 4.12 ± 0.72, 3.60 ± 0.57, 4.40 ± 0.50 and 4.84 ± 0.74 days. Total larval period of all the instars was completed in 23.20 ± 1.73 days before undergoing pupation in an earthen cocoon. The pupal period was of 13.48 ± 1.29 days. Male and female moths looked greenish-grey and orange brown, respectively. The female pupa was characterized by presence of tuft of hairs at the tip of the abdomen. Sex ratio (Male: Female) was 1:2.10. The pre, oviposition and post- oviposition periods were of 2.56 ± 0.50, 5.80 ± 0.86 and 2.40 ± 0.50 days, respectively. The fecundity of insect was 490.20 ± 77.87 eggs laid per female. Adult male and female longevities were of 9.50 ± 0.53 and 11.35 ± 0.86 days, respectively. Total life cycle of male and female insects was completed in 51 ± 2.97 and 53.76 ± 2.43 days, respectively.