Glass Vial Tied to Branch (IMAGE) University of California - Riverside Caption Clear glass vials containing 10-20 parasitoids each were attached to citrus branches with twist ties. When the lid of a vial was removed, the parasitoids dispersed to look for Asian citrus psyllids to attack. Credit Mike Lewis, CISR, UC Riverside. Usage Restrictions None License Licensed content 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.