EVALUATION OF STEINERNEMA-GLASERI (NEMATODA, STEINERNEMATIDAE) FOR BIOLOGICAL-CONTROL OF JAPANESE AND ORIENTAL BEETLES (COLEOPTERA, SEARABAEIDAE)

Steinernema glaseri Steiner were applied in autumn field trials agains t Japanese, Popillia japonica Newman, and oriental beetle, Exomala ori entalis (Waterhouse), larvae in 1992, 1993, and 1994. Nematodes were u sed in conjunction with various irrigation regimes and surfactants. Th e greatest reduction in larvae occurred where S. glaseri was used at 1 9.7 X 10(9)/ha and irrigated daily with 3.2 mm of water for 14 d. In 1 9 of 24 treatments where rates of 1.24-24.7 x 10(9)/ha were used with and without irrigation, S. glaseri reduced larval densities below a th reshold of 8/0.09 m(2). The use of 2 surfactants provided no additiona l control. Soil temperature data for Rhode Island revealed application s should be made before 1 September to maximize efficacy.