Epizootlological studies of Nomuraea rileyi in field population of Helicoverpa (=Heliothis) armigera occurring on tomato, field beans and vegetable pigeonpea, grown under uniform field conditions, showed higher rates of fungal infection in H. armigera found on vegetable pigeonpea (37%) than on field beans (28.2%) and tomato (20.5%). Further, H. armigera larvae collected from these host plants and reared on the respective host plants under laboratory conditions also revealed the same trend.