New strategies for phytoplasma vector control by semiochemicals
Phytoplasmas are worldwide responsible for more than 700 different plant diseases and have an important economic impact. Apple proliferation (AP), pear decline (PD) and European stone fruit yellows (ESFY) cause severe crop losses in European fruit growing regions. Phloem feeding insects were identified as vectors, often one species transmitting a specific phytoplasma. All investigated psyllid species use chemical cues for the identification of their host plants during migration between different host plant species. The production of plant volatiles was in some systems influenced by phytoplasma infections which indirectly influenced the behavior of vector insects. For several vector insects species-specific attractive and repellent compounds have been identified. Attractive compounds can be used in traps as lures for monitoring and mass trapping purposes. By combination of attractive compounds in traps and repellent compounds in dispensers these chemicals may be used in push-and-pull strategies.