Evaluation of Steinernema glaseri (Nematoda: Steinernematidae) for Biological Control of Japanese and Oriental Beetles (Coleoptera: Scarabaeidae)

Steinemema glaseri Steiner were applied in autumn field trials against Japanese Popillia japonica Newman, and oriental beetle, Exomala orientalis (Waterhouse), larvae in 1992, 1993, and 1994. Nematodes were used in conjunction with various irrigation regimes and surfactants. The greatest reduction in larvae occurred where S. glaseri was used at 19.7 × 109/ha and irrigated daily with 3.2 mm of water for 14 d. In 19 of 24 treatments where rates of 1.24-24.7 × 109/ha were used with and without irrigation, S. glaseri reduced larval densities below a threshold of 8/0.09 m2. The use of 2 surfactants provided no additional control. Soil temperature data for Rhode Island revealed applications should be made before 1 September to maximize efficacy.