Grape downy mildew
characteristic ‘oil spots’ on the upper surface of young, actively growing leaves, followed by downy white growth on the underside, are typical early [...] post-infection (depending on temperature and humidity), the disease is often well-established before it can be visually detected in the field. Leaf symptoms [...] to light-green oil spots on the upper leaf surface, often angular and limited by leaf veins White to greyish downy growth on the underside of leaves under