Field application of three entomopathogenic nematodes in the biological control of the larger black flour beetle (Cynaeus angustus) in cotton gin trash

The larger black flour beetle (LBFB) [Cynaeus angustus (LeConte) (Coleoptera: Tenebrionidae)] thrives in cotton gin trash piles in the Southern High plains of Texas. The use of entomopathogenic nematodes as biological control agent is being researched as part of identifying feasible tactics to reduce LBFB population in gin trash piles. LBFB become an occasional nuisance pest when beetles mass disperses from these piles to nearby homes and businesses. Cotton gin trash, plant material that is removed during the ginning process, is stored in mass piles in the agricultural landscape for multiple years at a time. LBFB adults and larvae feed on saprophytic fungi within these piles as well as burrow into the soil beneath them. A field trial in 2011 was conducted, individually testing infective juveniles of two laboratory strains (Steinernema riobravis, Heterorhabditis bacteriophora) and one commercial strain (Steinernema carpocapsae) in test plots at three locations. Periodic samples were taken for persistence and virulence testing of each nematode species as well as field monitoring of the beetle populations. S. carpocapsae showed both the highest persistence and virulence followed by S. riobravis and H. bacteriophora throughout the trial.