A rough distinction can be made between powdery mildew and downy mildew. Both deprive plants of important nutrients, which can lead to the death of the plant. Powdery mildew occurs mainly in dry and warm weather. It is characterized by a white, wipeable coating on the upper side of the plant. Later, the coating turns a dirty brown color. In contrast, downy mildew prefers humid and cool weather. The white coating can be found on the underside of the leaves, while the upper side has numerous yellowish-brown spots.

Whether it's your beloved roses or delicious zucchini that are affected, prevention is the best cure. When buying plants, look for resistant varieties. For roses, the ADR seal is a good indicator. For vegetable plants, the seed packaging will indicate whether they are resistant to powdery mildew and, if so, which varieties.

In addition to the right location, sufficient spacing between plants is also helpful. This ensures that young plants receive enough air and light to develop well. Moisture on young and still soft leaves is particularly conducive to fungal growth. It is therefore also important to ensure that only the base of the plant is watered. This is best done in the early morning hours. Over-fertilization also tends to promote powdery mildew infestation. This is because it makes the plant tissue soft and susceptible to pathogens.

If, despite attentive and careful care, a white coating appears on the leaves, it is important to act as quickly as possible. It is important to remove the heavily infested parts of the plant as soon as possible. No remains should be left on the beds, as the fungus spreads through air movement. It is best to dispose of the plant parts in the residual or organic waste. Disposal in your own compost is generally not recommended. Composting does not reliably render the powdery mildew spores harmless. The fungal spores also survive in the soil for a long time. Therefore, the soil under the plants should be protected with mulch or ground-covering plants. This prevents the spores from reaching the plants through the air.

There are various home remedies that are easy to make and effective against powdery mildew. A mixture of milk and water has proven to be effective. Mix raw or whole milk in a ratio of 1:8, for example, 100 milliliters of milk with 800 milliliters of water. Pour the mixture into a spray bottle and treat the affected areas several times a week. The lactic acid bacteria contained in the milk combat the fungus, and the sodium phosphate also contained in the mixture strengthens the plant.

As downy mildew spreads on the underside of the leaves, it is much more difficult to combat. A garlic decoction is effective against both types of mildew. To make it, chop four cloves of garlic and pour a liter of boiling water over them. Leave the decoction to steep until it has cooled down. Strain the garlic pieces and pour the decoction into a spray bottle. Spray the plants with the decoction every few days. Garlic contains active ingredients that inhibit fungal growth and damage the fungus.