Effects of turfgrass endophytes (Clavicipitaceae: Ascomycetes) on white grub (Coleoptera: Scarabaeidae) control by the entomopathogenic nematode Heterorhabditis bacteriophora (Rhabditida: Heterorhabditidae)

We evaluatcd the effect of endophyte infection in the two turfgrasses tall fescue (Festuca arundinacea Schreber) and Strong creeping red fescue (F. rubra L. ssp, rubra) on the susceptibility of three white grub species to the entomopathogenie nematode Heterohabditis bacteriophora Poiner Endophyte infection in strong creeping red fescue (only tested under greenhouse conditions) had no effect on nematode-susceptibility of third-instar oriental beetle (Exomala (=Anoinala) orientals Waterhouse) and northern masked chafer ( Cyclocerphala borealis Arrow). In tall fescue Linder greenhouse conditions, endophyte infection had a weak and variable enhancing effect on nematode-susceptibility of second- and third-instar F.orientalis and no effect on nemetode susceptibility of third-instar C. borealis and Popillia japonica, However under field conditions with natural white grub populations, endophyte infection in tall feseue had no significant effects on nematode efficacy against E. orientalis, P. japonica. and C. borealis. While it is possible that stronger interactions between endophytes and nematode-endophyte interactionms appear to be too variable to allow predictions on nemetode efficacy based on turfgrass endophyte status.