The grub Tomarus subtropicus Blatchley (Coleoptera: Scarabaeidae) is one of the most destructive pests of turfgrass and sugarcane (Saccharum spp.) in southern Florida, but its life cycle has only been described in sugarcane production. Preventive insecticides applied against T. subtropicus in turfgrass when adult activity and oviposition were expected in sugarcane have necessitated subsequent curative treatments. Thus, the seasonal activity of T. subtropicus was monitored using UV blacklight traps and by sampling soil in infested St. Augustinegrass lawns in Cape Coral and Punta Gorda, FL, during 2005–2006. Several preventive and curative insecticides and entomopathogenic nematode species were evaluated in laboratory, greenhouse and field tests. T. subtropicus is univoltine in both sugarcane and St. Augustinegrass, but adult flight peaked ≈1 mo later in St. Augustinegrass than in sugarcane. Halofenozide, clothianidin, and imidacloprid were effective preventive control products, and carbaryl and trichlorfon were satisfactory curative insecticides. The nematodes Steinernema scarabei (Stock & Koppenhöfer), S. glaseri (Steiner), and Heterorhabditis bacteriophora (Poinar) were most effective against T. subtropicus grubs, and second instars were more susceptible compared with third instars. Improved knowledge of the biology and effectiveness of different management options for T. subtropicus will help minimize excessive pesticide use, especially in coastal areas of Florida.