Abstract:

Sweet potato weevils (Cylas formicarius) are important quarantine pest both in the world. Understanding the genetic diversity of sweet potato weevils in different areas of China can provide the basis for its identification and quarantine. Genetic variations of the ITS-1 region were examined to probe the invasive sources for 6 populations from different areas in Southern China. Phylogenetic analysis on those sequences together with 35 known C. formicarius sequences showed that sweet potato weevil originated in India, then spread all over Asia from southeast to northwest along with the transportation of sweet potatoes. The phylogenetic tree consisted of two main clades (India and East Asia). The East Asia clade was further divided into two subclades (Northeast and Southeast). Chinese populations were all in two subclades of the Northeast subclade. It suggested that the 6 populations in China might come from the two origins and settled in China.