BIOLOGICAL-CONTROL OF JAPANESE, ORIENTAL, AND BLACK TURFGRASS ATAENIUS BEETLE (COLEOPTERA, SCARABAEIDAE) LARVAE WITH ENTOMOPATHOGENIC NEMATODES (NEMATODA, STEINERNEMATIDAE, HETERORHABDITIDAE)

Several strains or species of entomopathogenic nematodes-Steinernema carpocapsae Weiser (All), S. feltiae (=bibionis) (Filipjev) (Biosys strains 27 and 980), S. glaseri (Steiner), and Heterorhabditis bacteriophora (=heliothidis) Poinar (HP88)-were tested in the field for control of Japanese beetle, Popillia japonica Newman; Oriental beetle, Anomala orientalis Waterhouse; or black turfgrass ataenius, Ataenius spretulus (Haldeman) larvae. A spring field trial against A. orientalis, in which half of the plots were aerated to assist in nematode dispersal in soil, showed no significant differences between control plots and those treated with H. bacteriophora (HP88) or S. carpocapsae (All). A fall field trial in which half of the plots were dethatched before nematode application (to enhance nematode-larva contact) also showed no significant differences between plots treated with S. feltiae and control plots. Four other fall field trials with S. carpocapsae, S. feltiae, S. glaseri, and H. bacteriophora against Japanese beetle larvae showed a range of 0-81% control. The greatest mortality of P. japonica larvae occurred with S. glaseri at 24.7 x 10(9) per ha. A field trial with S. carpocapsae against A. spretulus showed 94% mortality at a 24.7 x 10(9) per ha rate.