Downy Mildew

This disease is caused by an oomycete called Peronospora or Plasmopara viticola. Only members of the vine family are prone to it. The disease spreads very rapidly and is very destructive. It will cause severe premature leaf-fall, leading to a reduction in vigour and a reduction in the quality and quantity of the harvest. The wood ripening is also adversely affected, leading to poor frost resistance.

It is another imported disease from the USA, first seen in France in 1878. Three years later, it was widespread throughout France and Algeria.

The following pages were prepared by James Cummings, FdSc Wine Production (Plumpton College)