What are the causes of the fungal disease?

Powdery mildew is caused by a fungus

Botany distinguishes between two species, the real and the false mildew, distinguished. Both diseases are caused by a fungus. As a rule, this pest specializes in a single plant variety. For example, cucumber powdery mildew does not affect roses.

Causes of powdery mildew

Powdery mildew is also known as the "fair weather fungus" because it forms when it is warm and dry. It sits on the upper side of the leaf and is visible through white spots that later form a dirty, brown film. You will mainly find powdery mildew on

• Asters
• Roses
• Cucumber
• Carrots
• and gooseberries

Causes of downy mildew

In contrast, downy mildew, the “bad weather fungus”, occurs when the air humidity is high. Symptoms appear on both the top and bottom of the leaf, with the film having a purple sheen and the spots being yellowish. Downy mildew affects most of all

• Cabbage
• radish
• Salsify
• peas
• Lamb's lettuce
• Lettuce
• spinach
• radish
• grapes
• and onions

Care mistakes that favor powdery mildew

Wrong pouring, Fertilize or plants promote the development of powdery mildew. Here are some things to look out for:

• too much nitrogen promotes fungus growth and weakens the plant's defenses. Dose the fertilizer conscientiously
• when watering, wait until the substrate is dry. Only water the roots, never the leaves and give the water in the morning if possible. Otherwise the liquid will build up overnight because it will not evaporate. The resulting moisture invites downy mildew
• Even too densely planted plants cause a high level of humidity in the environment, as the air cannot circulate sufficiently

Recurring powdery mildew

Powdery mildew again? You have only just completely cut the infected plant. But did you also pay attention to adequate care? Never just throw the infected branches onto the compost. From here the fungus spreads to settle on neighboring plants. It is best to burn the diseased shoots or dispose of them in the household waste.