New insect vectors of Elm yellows (associated with ‘Candidatus Phytoplasma ulmi’)
In North America, Elm yellows is a lethal disease of American elms (Ulmus americana) and other elm species. This disease is associated with ‘Candidatus Phytoplasma ulmi’ (EPPO A1 List), and several cicadellid species have been reported (Scaphoideus luteolus, Philaenus spumarius and Allygus atomarius) as vectors. On the campus of the Pennsylvania State University (US), it is estimated that since 2007 on a total of 400 mature elm trees, 82 have been killed by Elm yellows and Dutch elm disease. From July to September 2012, insects were collected using sweep nets and aspirators on branches of a red elm tree (U. rubra) showing symptoms of elm yellows, and on vegetation within a 0.5 km radius. Since 2007, this tree has repeatedly been tested and found positive for ‘Ca. Phytoplasma ulmi’. Approximately 600 cicadellid insects were collected. Transmission trials on collected insects showed that Lepyronia quadrangularis, Philaneus spumarius and a leafhopper belonging to the genus Latalus were vectors of ‘Ca. Phytoplasma ulmi’. During this study, no specimens of the main vector, S. luteolus, were caught. According to the authors, this is the first time that Lepyronia quadrangularis and Latalus sp. are recorded as vectors of ‘Ca. Phytoplasma ulmi’.
Sources
Rosa C, Mc Carthy E, Duong K, Hoover G, Moorman G (2014) First report of the spittlebug Lepyronia quadrangularis and the leafhopper Latalus sp. as vectors of the Elm yellows associated phytoplasma, Candidatus Phytoplasma ulmi in North America. Plant Disease 98(1), 154-155.