Insect diversity in chickpea ecosystem

A study on the insect diversity in chickpea ecosystem was carried out in the field at Pulse Section, Agricultural Research Institute, Tandojam during winter of 2007-2008. Three insect pests (Helicoverpa armigera, Spodoptera litura and Agrotis ipsilon) and four natural enemies (Geocorisspp, Oriusspp, Delta sp and Coccinella undecimpunctata)were recorded from the study plots. The results indicated that the larval instars of cutworms Helicoverpa armigera, Spodoptera litura and Agrotis ipsilon infested on tender foliage, developing buds and pods. The larval population was recorded from January to March on chick pea. The data revealed that over all mean population among three cutworm, H. armigera population was significantly highest (74.25) as compared to S. litura (55.25) and A. ipsilon (42.12). The statistical analysis of data suggested that there were highly significant differences between cutworms population (P<0.01). The total mean population of the three pests was maximum (34.75) on 2nd March with a slope of line 5.008X and r2 = 0.93. The population was minimum (0.87) with declining curve -0.049 and R-square was (r2 =-0.84), it depicted that there was 84 percent variation in the population of insect pest due to date intervals. The data further revealed that over all mean population among natural enemies, Orius sp population was significantly highest (32.75) as compared to C. undecipunctate(10.25), Geocoris sp. (3.65) and Delta sp.(2.25) The statistical analysis of data suggested that there were highly significant differences between population of natural enemies (P<0.01). The total mean population of the natural enemies (Fig. 11) was maximum (34.75) on 2nd March with a slope of line 1.258X it indicated that the population increased with a rate of 1.258. R-square was (0.94) it depicted that there was 94 percent variation in the population of predator was due to date intervals. The population was minimum (0.87) with declining curve -1.4X and R-square was (r2 =0.96), it depicted that there was 96 percent variation in the population of natural enemies due to date intervals. It can be concluded that natural enemies, specially the predators occurred in chickpea crop and preyed on the eggs and young larvae of cutworms. Among others the Orius sp. and Coccinellids have the potential in regulating the pest suppression on chickpea crop. This could be suggested that the natural enemies may be utilized by mass rearing and releasing in chickpea fields for as a potential component of biological control of harmful insect pests.