2022 年 66 巻 4 号 p. 159-164
In recent years, damage caused by flower thrips, Frankliniella intonsa（Trybom）（Thysanoptera: Thripidae）, has spread in strawberry fields throughout Japan. Furthermore, cases of F. intonsa developing resistance to existing insecticides have been reported. In this study, to investigate the presence of symbiotic bacterial infections, F. intonsa samples were collected from strawberry fields in Oyama City, Tochigi Prefecture. Symbiotic bacteria are known to affect the survival, reproduction, sex ratio, and insecticide susceptibility of their hosts. Diagnostic polymerase chain reaction and sequencing analysis showed that a portion of the surveyed population of F. intonsa（30.8%）were infected with the symbiotic bacterium Wolbachia. Notably, the Wolbachia infection rate of larvae rapidly increased from 17.4 to 44.8% within just 1 month. These results suggest that Wolbachia infection may have benefitted the host. This is the first report of Wolbachia infection in a population of Japanese F. intonsa. Future studies investigating the function of Wolbachia may facilitate the development of novel methods for controlling thrips using symbiotic bacteria.