A serious pest insect Bemisia tabaci (Gennadius) consists of at least 24 genetic groups. In addition to the genetic groups, their symbiotic bacteria reportedly affect the ecological natures of B. tabaci such as the ability of these insects to transmit phytopathogenic viruses and resist insecticides. Thus, it is important to identify the genetic groups and the symbiont infection status for effective pest control. Here, we describe a multiplex diagnostic method that clearly identified three invasive and an indigenous genetic group (MEAM1, MED Q1, MED Q2 and Asia II 6) and seven symbionts (Portiera, Hamiltonella, Rickettsia, Cardinium, Wolbachia, Arsenophonus and Hemipteriphilus) of B. tabaci. Our methods enabled up to 83 % time saving and 67 % cost reduction, compared to the conventional methods, due to the following features: (1) crude DNA samples were used; (2) multiplex PCR greatly reduced the number of PCR experiments necessary; (3) restriction enzyme digestion was not required; (4) 250 V electrophoresis using sodium borate buffer yielded well-separated band patterns in only 10 min.