Oviposition and larval development of Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae) in relation with chickpea, Cicer arietinum L. (Fabaceae) crop phenology

This paper presents five years (1994-1998) studies conducted on natural infestation of the cotton bollworm, Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae) on different growing stages of chickpea Cicer arietinum (Fabaceae). The studies revealed that the oviposition peak of H. armigera was presented during 1st to 3rd week of April at 60 to 100% flowering and 30 to 70% pudding stage of the crop. The population peak of 2nd instar larvae was noted between 15 April 1997 (earliest) and 27 April 1995 (latest) generally at full pudding stage and the population peak of 3rd instar larvae was 1st fortnight of April to 19 April 1995 to 3 April 1991 (latest) over the study period. The population peak of 4th instar was recorded from 03 May (earliest in 1995) to 26 May (latest in 1996) at full pudding and 15% maturity of the crop. Highly significant linear regression and coefficient of determination were R2 = 0.3553 at p less than 0.01 d.f. = 17, R2 = 0.6825 at p less than 0.001 d.f. = 16, R2 = 0.7611 at p less than 0.001 d.f. = 21, R2 = 0.5521 at p less than 0.001 d.f. = 25 and R2 = 0.8168 at p less than 0.001 d.f. = 20 for per year, 2, 3, 4 and 5, respectively between H. armigera trap catch population and number of egg per plant. The linear regressions between the number of adults and 1st instar larvae were significant at p less than 0.05 and p less than 0.001 with significant positive correlation (r = 0.59, r = 0.57, r = 0.80, r = 0.71 and r = 0.92 in per year, 2, 3, 4 and 5, respectively) and regression trends between eggs and 1st instar were significant at p less than 0.05, p less than 0.001, p less than 0.001 and p less than 0.001 with r = 0.43, r = 0.74, r = 0.69, and r = 0.89 in year-2, 3, 4 and 5, respectively. The results of this study could be helpful in launching appropriate, economical and environmentally non-disruptive insect pest management practices with special reference to management of H. armigera in an integrated pest management (IPM) programmes.