Development of allele-specific loop-mediated isothermal amplification (AS-LAMP) to detect the tebufenozide-resistant allele in the smaller tea tortrix, Adoxophyes honmai (Lepidoptera: Tortricidae)

The smaller tea tortrix, Adoxophyes honmai Yasuda (Lepidoptera: Tortricidae), is one of the most common pests that affect the tea plant, Camellia sinensis (L.) O. Kuntze. Diacylhydrazine-analog insect growth regulators, such as tebufenozide, have been used as controls; however, the species began showing resistance to this compound in approximately 2004. Previously, we identified an amino acid mutation (A415V) in the ecdysone receptor gene (EcR) as a principal factor in tebufenozide resistance and developed a molecular diagnostic method to detect the EcR A415V mutation through polymerase chain reaction-restriction fragment length polymorphism (PCR–RFLP). However, for the continuous management of tebufenozide resistance in A. honmai, a simple and quick genetic diagnostic method that does not require specialized equipment is preferable. In this study, we developed a novel technique to detect the mutation using allele-specific loop-mediated isothermal amplification (AS-LAMP). This method enables the monitoring and detection of tebufenozide-resistance alleles much faster than PCR–RFLP and with moderate accuracy. Therefore, it could be a powerful tool for the early detection of tebufenozide-resistant A. honmai in tea plantations.