Whiteflies on a Plant Leaf (IMAGE) University of Arizona Caption Sweet potato whiteflies are often seen in pairs, like these two on a plant leaf. UA researchers discovered that Rickettsia bacteria give the tiny pests an evolutionary edge over their non-infected peers. Credit Stephen Ausmus Usage Restrictions Usage only granted in conjunction with posting/reporting of this news release. Credit must be shown as indicated. 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.