Hemlock Woolly Aldegid (image) University of California - Santa Barbara Caption This shows high densities of the hemlock woolly adelgid, an insect native to East Asia that feeds by sucking sap from hemlock trees. In North America, it poses a major threat to eastern and Carolina hemlocks. Credit University of California Santa Barbara Usage Restrictions None Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.