Coincidence of maximum severity of powdery mildew on grape leaves and the carbohydrate sink‐to‐source transition

摘要: Grapevine leaves infected with powdery mildew are a source of inoculum for fruit infection. Leaves emerging on single primary shoot Vitis vinifera cv. Cabernet Sauvignon were exposed to average glasshouse temperatures 18°C (0
23 emerging/day) or 25°C (0
54 emerging/day). All 8–10 shoots approximately 20 leaves each inoculated Erysiphe necator conidia assess disease severity after 14 days in the glasshouse. Two photosynthetic ‘source’ per remaining treated 14CO2 identify, by autoradiography, leaf position completing carbohydrate sink-to-source transition. There was clear association between mean modal maximum (position 3
7 18°C; 4
4 for 25°C) and transition 3
8 position 4
7 25°C). The percentage germinating form secondary hyphae 4
2 additional plants grown glasshouse. A higher rate emergence resulted a greater proportion diseased shoot. Bayesian model, consisting component models severity and ontogenic resistance, had parameters representing magnitude pathogen colonization that differed for developing different preinoculation environments. results support hypothesis population of vineyard