Studies on the adult's winter hardiness of Galerucella birmanica Jacoby (Coleoptera: Chrysomelidae)

Cold hardiness of water chestnut beetle (Galerucella birmanica Jacoby) in different overwintering periods in Yangzhou area and that in the same overwintering period in different areas were compared by measuring their super-cooling point (SCP). The results showed that the over-wintering adults had different cold-hardiness at different time. The super-cooling point reached the lowest in middle winter. The over-wintering adults collected from different latitudes also showed some differences in cold-hardiness. The SCP was dropping with the latitudes increasing.