Résumé
The relative durations of incubation (the time between inoculation and symptom expression) and latency (the time between inoculation and infectiousness of the host) are poorly documented for plant diseases. However, the extent of synchrony between the ends of these two periods (i.e. their mismatch) is a key determinant of the epidemic dynamics of many diseases and consequently is of primary interest in the design of disease management strategies. In this study, an experimental approach to assess this mismatch is presented and applied on sharka, a severe disease caused by Plum pox virus (PPV) on trees belonging to the Prunus family. Leaves of previously inoculated young peach trees were used individually as viral sources in aphid-mediated transmission experiments carried out at three time points post inoculation to bracket symptom onset. By fitting a binomial generalized linear model to the obtained transmission rates, we demonstrated that the first symptoms appear on a leaf 1 day be fore it rapidly becomes infectious. Therefore, under our experimental conditions, latency and incubation of PPV infection are almost synchronized.