Powdery mildew on apple trees is a dreaded disease in our latitudes. The disease also spreads quickly in crabapples after infection. If left untreated, apple powdery mildew can lead to reduced and stunted blooms and crop failure.
How do I recognize powdery mildew on crabapples?
On apple trees and crabapples, powdery mildew can be recognized by a white, powdery coating on the upper side of the leaves. The shoots can often already be seen in the form of spread bud scales. There are dried tufts of leaves on the tree.
What caused powdery mildew on crabapples?
Apple powdery mildew is themildew fungusPodosphaera leucotricha, which isspread by the wind. It attacks all Malus varieties, whether crabapple or garden apple. When it is dry and warm, the fungus germinates on the leaves of the trees. From there, the mycelium continues to develop over the leaves and branches. The infestation is favored by morning dew. The fungus removes water and nutrients from the leaves. That's why they dry up and die.
How can I combat apple mildew?
You can first combat powdery mildew on crabapples bycutting back the affected shoots Since the fungus overwinters on the buds, you should start with it in early spring. In an organic garden you avoid using fungicides. Instead, choose home remedies such as a mixture of fresh milk and water in a 1:2 ratio as a spray. A mixture of baking powder, rapeseed oil and water also works effectively as a spray against mildew.
How do I prevent powdery mildew on crabapples?
To avoid mildew on trees, you should water young trees in dry weather. When fertilizing, make sure that the nitrogen content is not too high. Too much nitrogen causes the leaves to become soft, creating a breeding ground for a fungal infection. If a crabapple in your garden has already become infected, you should water the other malus trees with field horsetail as a preventive measure.
Tip
Resistant varieties
Mildew you can also avoid using resistant varieties. Malus 'Everest' and 'Roy alty' show great robustness against mildew. The variety 'Red Jade' is even resistant to mildew.
