Oviposition and larval development of Helicoverpa armigera (Hübner) (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 (hübner) (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% podding stage of the crop. the population peak of 2 nd instar larvae was noted between 15 april 1997 (earliest) and 27 april 1995 (latest) generally at full podding 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 podding and 15% maturity of the crop. highly significant linear regression and coefficient of determination were r 2 = 0.3553 at p <0.01 d.f. = 17,r2 = 0.6825 at p <0.001 d.f. = 16,r2 = 0.7611 at p <0.001 d.f. = 21,r 2 = 0.5521 at p <0.001 d.f. = 25 and r2 = 0.8168 at p <0.001 d.f. = 20 for year 1,2,3,4 and 5,respectively between h. armigera trap catch population and number of egg plant-1. the linear regressions between the number of adults and 1st instar larvae were significant at p <0.05 and p <0.001 with significant positive correlation (r = 0.59,r = 0.57,r = 0.80,r = 0.71 and r = 0.92 in year 1,2,3,4 and 5,respectively) and regression trends between eggs and 1st instar were significant at p <0.05,p <0.001,p<0.001 and p<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. © 2012 zoological society of pakistan.