Empoasca sp. (IMAGE) Max Planck Institute for Chemical Ecology Caption Leafhopper of the genus Empoasca on a tobacco leaf: A research team at the Max Planck Institute for Chemical Ecology in Jena has now elucidated the chemical defense that tobacco plants use to defend themselves against this plant sap-sucking pest. Credit Danny Kessler, Max Planck Institute for Chemical Ecology Usage Restrictions Credit must be given to the creator. License CC BY 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.