author(s)
Kiran Bala and Surjeet Kumar

abstract
The bean bug Chauliops fallax feeds exclusively on all leguminous crops in most regions of the world. The population density and spatial distribution of bean bug has been investigated on three different host plant i.e. soybean, cowpea and black gram (mash) under mid hill conditions of Himachal Pradesh during 2016. The fields of 600m² and 300m² area were selected as a sampling unit for sampling in soybean, cowpea and black gram. Him Palam Hara Soya -1, C-475 and Pant U19 genotypes of soybean, cowpea and mash were selected for the estimation of density and distribution of the bean bug. Different methods viz., Morisita’s index, Index of dispersion and Lewis index were used to calculate the density and distribution of the population of the pest. The mean population of bugs per plant was recorded on soybean (7.25) followed by cowpea (3.01) and black gram (1.21). Studies on knowing the distribution pattern of bean bug population under field conditions revealed that in soybean the distribution of bug was contagious (2.99) while in cowpea (2.44) and black gram (1.87) regular and contagious distribution pattern was found. The Z value of Morisita’s index in case of soybean was 9.98 followed by 5.87 and 3.50 in case of cowpea and black gram. Similar trend was found in case of Index of dispersion and Lewis index. Optimum sample sizes for estimates of the pest density in all the three host plants are presented.