Numbers of Phyllophaga vetula (Horn) (Coleoptera: Melolonthidae) larvae killed after application of nematodes Steinernema glaseri Steiner, Heterorhabditis bacteriophora Poinar, and Steinernema feltiae Filipjev at five concentrations (50, 100, 200, 500, and 1,000 nematodes per larva) in aqueous suspension were compared. Lethal concentrations and times for each species were determined. The difference between the treatments was very significant. The nematode most effective for pest control was S. glaseri at a dose of 1,000 per larva that killed 97.5%. H. bacteriophora at the same dose killed 87.5%, and S. feltiae killed 60.0%. With 500 per larva, all three nematodes were statistically the same. S. glaseri at any concentration had the lowest lethal concentration (LC₅₀ and LC₉₅) and lethal time (LT₅₀ and LT₉₅), followed by H. bacteriophora and S. feltiae. The three species of nematodes showed a positive dose-response relationship.