Natural enemies and site characteristics affecting native and invasive white grubs (Coleoptera: Scarabaeidae) on transition-zone golf courses

White grubs and their natural enemies were sampled on 29 Kentucky golf courses, the first such survey in the transitional climate zone. Native Cyclocephala spp. comprised 67.3% of the total grubs, outnumbering P. japonica at 27 of the 43 study sites. Entomopathogenic nematodes, Tiphia vernalis and T. pygidialis, and milky disease were the most common natural control agents, although bacteria (Serratia entomophila and S. marcesens) and Metarhizium anisopliae also were found. Microsporidia (Ovavesicula ) and gregarines previously reported elsewhere were uncommon or absent at our sites. Abundance of particular grub species or pathogens showed no correlations with site factors including pH, soil composition, and organic matter.