EVALUATION OF STEINERNEMATID NEMATODES AGAINST POPILLIA-JAPONICA (COLEOPTERA, SCARABAEIDAE) LARVAE - SPECIES, STRAINS, AND RINSE AFTER APPLICATION

We evaluated the efficacy of Steinernema glaseri Steiner (strains NC, NJ-43, and a strain genetically selected for improved efficacy, SI-12) , Steinernema anomali Kozodai (Ryazan strain), and Steinernema sp. (RG V strain) for the control of Japanese beetle, Popillia japonica Newman , larvae in the laboratory and field. Virulence of nematodes was asses sed by the mortality of the host larvae and by the number of nematodes established per host. In laboratory tests, NJ-43 and SI-12 strains of S. glaseri were significantly more virulent to larvae than the NC str ain, S. anomali or Steinernema sp. Similar results were obtained in fi eld tests, where the NJ-43 and SI-12 strains produced 66 and 65% reduc tions of Japanese beetle larval population as compared with the NC str ain that produced a 44% reduction. Steinernema anomali and Steinernema sp. were as effective as the NC strain of S. glaseri. Nematodes could be successfully applied during midday, if washed from the grass surfa ce with a rinse after application. We conclude that the choice of nema tode strain and rinsing of nematodes after application are important f actors in obtaining control of Japanese beetle populations in turfgras s.