Powdery mildew and downy mildew

What do the powdery mildew species have in common?

Cause of powdery mildew is in in both cases a species of fungus. However, the pseudofungus in downy mildew is more closely related to diatoms. The parasites settled on or in the leaves. Then they suck nutrients and moisture from the cells of the leaves.

How does powdery mildew manifest itself?

If the coating of powdery mildew has spread, appear brown, dried spots on the leaves. The fungal mycelium forms suckling appendages that draw nutrients and moisture from the leaves. This limits the metabolism of the cells and they die. As it spreads, the leaves die first, and in the worst case, the whole plant dies. The fungus needs heat to grow and is therefore also called the “fair weather fungus”.

How do I recognize downy mildew?

Downy mildew usually only gets through brown spots on the upper side of the leaf discovered. These are already damaged cells. Only a look at the underside reveals the mushroom lawn. Downy mildew requires a lot of moisture to grow. The mushroom penetrates into the interior of the leaf and feeds on the cell juices. This creates the brown oil stains on the top. Because it needs moisture, the fungus occurs mainly in spring and autumn. That is why it is also called the "bad weather mushroom".