The effects of several commercial oil insecticides, as well as entomopathogenic fungus, Beauveria bassiana, and entomopathogenic nematode, Heterorhabditis bacteriophora were observed against adult japanese beetle Popillia japonica Newman, when beetles were made to walk through a tube and across a sponge containing a treatment. A direct mortality test and an efficacy test were carried out. The Beauveria bassiana treatment was the most effective in the mortality test. A bioassay was conducted to test the ability of several nematode isolates to kill the adult japanese beetle. Adult japanese beetles were then collected from the field and made to run through a tube, in which they were exposed to either Heterorhabditis bacteriophora GPS-11 strain, Steinernema carpocapsae, or Beauveria bassiana. Mortality was observed, as well as the ability of exposed beetles to contribute to the mortality of unexposed beetles.