Weather conditions in the last 48 hours have caused Powdery Mildew to spread rapidly in poorly protected vineyards. These pictures were all taken today and show very fresh sporulation and leaf, stem and, most concerning infloresence infection - below.
Once established in a vineyard like this Powdery Mildew is almost impossible to remove. Powdery Mildew is a creeping disease. It ‘hides’ deep in the canopy. Under humid overcast conditions Powdery multiples more quickly.
Powdery doesn’t need rain to spread, but it does do well in the humid conditions before and after rain showers.
In the vineyard pictured the level of powdery mildew is already threatening to affect the quality of the fruit and leaf infections are very easy to see - below.
Powdery is a MAJOR concern in blocks which have a history of disease.
The good news is good coverage = good disease control. Good effective sprays now before the canopy gets too big to spray are worthwhile.