Abstract
To discriminate Helicoverpa armigera and H. assulta, a 557 bp portion of the 16S ribosomal RNA gene of the mitochondrial DNA was analyzed by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Results of nucleotide sequencing of the amplified DNA products from the two species showed that they could be easily discriminated from each other by MseI- or VspI-digestion of the PCR products. In practice, 227 dried adult specimens of the two species that were identified morphologically in advance were correctly discriminated by the PCR-RFLP patterns with MseI or VspI. This method was applied to the larvae of Helicoverpa species feeding in tobacco fields. Analyses of PCR-RFLP patterns of individual larvae collected at 17 fields in Iwate, Yamagata, Fukushima, Tochigi, Okayama, and Okinawa prefectures, showed that H. armigera widely coexists with H. assulta. Intraspecific variation in the RFLP patterns was rarely detected.
