Pupal duration, survival and occurrence of summer and winter diapause in Helicoverpa armigera (Hübner) under field conditions Kumar Sarwan1, Saini R.K. Department of Entomology, CCS Haryana Agricultural University, Hisar - 125 004, Haryana, India. 1Present Address: Oilseeds Section, Department of Plant Breeding and Genetics, Punjab Agricultural University, Ludhiana-141004, Punjab, India. E-mail: sarwanent@yahoo.com, sarwanent@gmail.com. Abstract In two year study grown up H. armigera larvae were collected from cotton crop and other hosts, reared and allowed to pupate in the laboratory in the soil-filled plastic specimen tubes (10 x 4.5 cm). Such tubes were fixed in cotton field and kept under observation to record moth emergence, and pupal duration and survival. Based on the duration criterion, there was an occurrence of both summer and winter facultative diapause in this pest. During April-May, the duration of non–diapausing pupae was 12 days, while the diapausing pupae took duration of 57–70 days. During September to November, large variations in pupal duration were observed during both the years. During 1st year 64.43 per cent pupae took duration of 9–14 days and 0.52 per cent took 99–112 days. Similarly, during 2nd year 56.34 per cent pupae took 9–14 days, while 1.60 per cent took 99–126 days. The remaining pupae had an intermediate duration. This also indicated the presence of winter diapause. Pupal mortality during different weeks was quite variable. It was highest (>87%) during April-May mainly because of high summer temperature and low relative humidity. About 3 per cent mortality during this period was due to ants. Predation by ants was the major pupal mortality factor during 1st crop season causing 3.7–46.2 per cent mortality during September-early October, as compared to 2.94 per cent during 2nd. During October-December the major factors causing pupal mortality were blockage of emergence tunnels and unknown reasons. Pooled mean pupal mortality during the crop season was 26.79 and 39.45 per cent in 1st and 2nd, respectively. Top |