Competition among Flavescence Dorée Phytoplasma Strains in the Experimental Insect Vector Euscelidius variegatus

Phytoplasmas are plant pathogenic wall-less bacteria transmitted in a persistent propagative manner by hemipteran insects, mainly belonging to the suborder Auchenorrhyncha (Fulgoromorpha and Cicadomorpha). Flavescence dorée (FD) is quarantine disease of grapevine, causing great damage European viticulture associated with phytoplasmas 16SrV-C (FD-C) -D (FD-D) subgroups. FD-C FD-D strains share similar pathogenicity, but mixed infections rare nature. To investigate competition among FDp strains, specimens laboratory vector Euscelidius variegatus (Hemiptera: Cicadellidae) were forced acquire both phytoplasma haplotypes upon feeding on FD-C- FD-D-infected plants or after injection strains. The pathogen colonization insect bodies heads was monitored multiplex qPCR, efficiencies transmission estimated. Single infection, irrespective strain type, more frequent than expected, indicating that FD occurs. Hypotheses for resources and/or host active sites direct antibiosis one against other discussed, based genetic complexity populations high genome variability strain. As management still relies insecticides vectors, characterization description their epidemiology also have practical implications.