A rapid LAMP-based colorimetric assay with quick DNA extraction for on-site identification of Drosophila suzukii Matsumura

The spotted wing drosophila, Drosophila suzukii Matsumura (Diptera: Drosophilidae), distributes in most soft-skinned fruit areas in China, is an economically important pest of fresh cherries during Sino-European trade and is considered a quarantine pest in A2 list by European and Mediterranean Plant Protection Organization. Loop-mediated isothermal amplification (LAMP) is an accurate, quick and convenient molecular identification method, applied to distinguish D. suzukii from other fruit flies. This method can be used for inspection in the field, and at the points of entry (POEs), because its results can be detected with the naked eye due to colour changes. In our study, first, we reported a simple and fast LAMP colorimetric detection method for molecular identification of D. suzukii. We designed primer sets for D. suzukii based on mitochondrial cytochrome oxidase I (COI) sequences. The specificity and sensitivity of the primers were tested by using target and non-target fruit flies in the family Drosophilidae and Tephritidae, usually intercepted during the Sino-European cherry trade. Second, for detection in the field and at POEs, the adoption of a quick DNA extraction method could save the total time of LAMP identification to about 90 min. Taken together, this accurate, quick and convenient LAMP-based colorimetric identification assay combined with a quick DNA extraction method could visually detect clearly with just one portable heating device, which will be useful for rapid on-site identification and inspection for D. suzukii by the quarantine department.