Minor cultures as hosts for vectors of extensive crop diseases: Does Salvia sclarea act as a pathogen and vector reservoir for lavender decline?

• Published in: Journal of pest science Vol. 91; no. 1; pp. 145 - 155
• Main Authors: Chuche, Julien, Danet, Jean-Luc, Rivoal, Jean-Baptiste, Arricau-Bouvery, Nathalie, Thiéry, Denis
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.01.2018; Springer Nature B.V; Springer Verlag
• Subjects: Adults; Agriculture; Animal biology; Biomedical and Life Sciences; Crops; Disease transmission; Ecology; Entomology; Forestry; Herbivores; Host plants; Hyalesthes obsoletus; Insects; Lavandula; Lavandula intermedia; Life cycle analysis; Life cycle assessment; Life Sciences; Original Paper; Phytopathology and phytopharmacy; Phytoplasma; Plant diseases; Plant Pathology; Plant Sciences; Population decline; Salvia sclarea; Seedlings; Signs and symptoms; Stolbur; Uprooting; Vectors; Vegetal Biology; Lavender decline; rearing; Bois noir; Host plant shift; Phytoplasma; insecte vecteur; pathologie végétale; plant health; insect vectors; lavandula; phytopathogenic bacteria; santé des plantes; bactérie phytopathogène; Hyalesthes obsoletus rearing
• ISSN: 1612-4758; 1612-4766
• DOI: 10.1007/s10340-017-0885-5

Stolbur is a phytoplasma disease affecting crops worldwide. The planthopper Hyalesthes obsoletus is the main natural vector of ‘ Candidatus Phytoplasma solani’ responsible of stolbur. In France, lavender ( Lavandula angustifolia ) and lavandin ( Lavandula  ×  intermedia ) are strongly affected by this phytoplasma. These plant species are both hosts for the phytoplasma and its insect vector. In 2011, catches of adults were exceptionally sizable on one of the clones of lavandin most tolerant to lavender decline. A high population level of ‘ Ca. P. solani’ vector was also observed on the adjacent plot of clary sage, Salvia sclarea . In order to clarify the potential role of S. sclarea as a host plant for H. obsoletus and ‘ Ca . P. solani,’ we conducted field surveys and laboratory experiments. The uprooting of clary sage and root examination showed the presence of nymphs during winter. Harvested nymphs have been reared on S. sclarea from seedlings in a greenhouse for many generations. By performing its whole lifecycle on clary sage, we demonstrated for the first time that S. sclarea is a host plant of H. obsoletus and could be a source of stolbur vector. Nevertheless, status of clary sage as host plant of phytoplasma in the field up to now is not so clear. On 42 Q-PCR runs done on S. sclarea , 41 were negative to the phytoplasma, and one positive. Experimental transmission with infected H. obsoletus sampled on infected lavender showed that clary sage plant could be infected, expressed symptoms and multiplied ‘ Ca. P. solani.’