Rapid and highly accurate detection of Drosophila suzukii, spotted wing Drosophila (Diptera: Drosophilidae) by loop-mediated isothermal amplification assays

Abstract

Drosophila suzukii, the spotted wing drosophila (SWD), is currently a major pest that causes severe economic losses to thin-skinned, small fruit growers in North America and Europe. The monitoring and early detection of SWD in the field is of the utmost importance for its proper management. Although SWD traps using various attractants have been developed and used for SWD monitoring in the field, they are not specific to SWD; consequently, other insects, including Drosophilidae flies that share high morphological similarities with SWD, are also easily trapped. Thus, all captured flies need to be identified under microscopes by an expert in fly morphological characteristics. In this study, we developed a simple molecular detection tool that rapidly and accurately identifies SWD without sophisticated instruments or expertise. We first identified a gene, Ds10_00012111, that is present in the SWD genome but not in that of any other insect species. Then, we developed the loop-mediated isothermal amplification (LAMP) assay, which was designed based on genomic DNA of the Ds10_00012111 gene. This LAMP assay detected only genomic DNA from SWD—not from Drosophila melanogaster. The minimum amount of genomic DNA required for the LAMP assay was 1.0 picogram, and the duration of this assay at temperatures ranging from 58°C to 62°C was 30min. In addition, this assay could detect genomic DNA in SWD geographical strains collected from 8 different locations in Asia, Europe, Hawaii, and the USA. Our LAMP assay could be a useful detection tool for identifying SWD rapidly in the field.