The Black Grass Bug (Labops hesperius Uhler): Its Effect on Several Native and Introduced Grasses

Abstract

Large areas of Utah's rangeland have been seeded to introduced wheatgrasses, and many of these areas are now infested with the black grass bug (Labops hesperius). A study of the effects of this insect pest on several native and introduced grasses was conducted on three experimental study plots in southwestern Utah. The data revealed that the six introduced grass species studied, growing in small monocultures, contained considerably more black grass bugs than did the native range grasses in nearby areas. Thus, the six monoculture grass species were more susceptible to grass bug damage than were the native range grasses. Moreover, variations in black grass bug populations within the six grass monocultures also revealed differences in susceptibility. Phenology comparison data revealed there was no correlation between the phenological stage of plant development and the stage of black grass bug instar development, therefore ruling out an accurate means of determining time of spraying in relation to plant maturation.