Source estimation and molecular diagnostics for an emerging pest in the Western hemisphere, the cotton jassid, Amrasca biguttula

The cotton jassid, Amrasca biguttula (Ishida, 1913) (Hemiptera: Cicadellidae), is an “Old World” agricultural pest with a wide host range, including at least cotton, eggplant, okra, and sunflower. In the Western Hemisphere, the cotton jassid is invasive in Puerto Rico and the Caribbean. Despite its ubiquity and impact across its native range, the species remains poorly described with regards to population structure and genetic diversity. The barcoding region of the cytochrome c oxidase subunit I (COI) gene has been characterized in populations infesting cotton and vegetables in India, the Punjab region of India and Pakistan, and the Philippines, but high-quality data from other regions where the species occurs are not readily available. In this study, we used DNA barcoding to confirm the species identification of cotton jassids infesting agricultural areas in the Puerto Rico and the Caribbean. Additionally, we attempted source estimation by aligning the Caribbean specimens’ barcode sequences to a curated database of 105 previously published sequences from the species’ native range. In its native range, A. biguttula barcoding is characterized by the presence of a single dominant haplotype and a high diversity of rare haplotypes. These rare haplotypes are typically only a few base pairs different from the dominant haplotype. In our dataset, we found a distribution of haplotypes consistent with this pattern. Work remains ongoing to expand genetic information for this species and to develop new rapid diagnostic tools that will facilitate early detection of this species.