The multiplication kinetics of the Flavescence dor,e phytoplasma in broad bean after inoculation by the experimental vector Euscelidius variegatus was determined. The number of phytoplasma cells, measured by quantitative real-time PCR in the aerial parts of the plants, increased exponentially over the time. After 22 to 30 days post inoculation, when symptoms appeared, bacterial growth reached a stationary phase. Whatever the time following inoculation there were no statistical differences between numbers of phytoplasma cells in plants infected by Map-FD1 (FD-CAM05) and Map-FD2 (FD92 and FD-PEY05) genotype strains. On the contrary, temperature had an influence on Flavescence dor,e phytoplasma multiplication which was nearly twice as fast in broad beans incubated at 25 A degrees C than in broad beans incubated at 20 A degrees C. At 25 A degrees C, plants expressed symptoms 1 week earlier. In a context of climate change, the consequences of a global warming on the Flavescence dor,e epidemics are discussed.