Pure garden joy when you can finally harvest the first cucumbers in summer. But be careful! Joy often suddenly turns into anger when white, flour-like spots or a gray coating appear on cucumber leaves. Powdery mildew - the dreaded cucumber disease - how do you get rid of it quickly and permanently?
What causes powdery mildew on cucumber leaves?
The pathogen is a fungus. Both powdery mildew and downy mildew usually appear at the end of July and attack cucumber plants both outdoors and in the greenhouse.
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Powdery mildew threatens cucumber plants in dry summer weather. It is found on the leaf surfaces as a floury-white mushroom lawn. Within a short time the leaves brown and dry up and the cucumber plants die.
Downy mildew spreads in damp weather, rain and, depending on the type of fungus, at temperatures of 10 ° to 18 ° degrees. It covers the underside of the cucumber leaves with a purple-gray spore lawn. Within a few days, the cucumber leaves turn yellow and die from the edge.
It doesn't rain in the greenhouse, but if the humidity is too high, downy mildew will also spread. Therefore, ventilate the greenhouse well both during the day and at night.
Effectively prevent cucumber mildew
The safest measure to prevent cucumber mildew: Only grow mildew-resistant F1-hybrid cucumbers such as:
- Burpless Tasty Green
- Jazz musicians
Fight cucumber powdery mildew - the most effective home remedies
Harvesting cucumbers without powdery mildew can be effective both preventively and to save the cucumber plants with these recipes:
- Skimmed milk
- Nettle manure
- Sakhalin knotweed infusion
- baking powder
Dilute skimmed milk 1: 6 with rainwater. Spray over the leaves once a week and water the cucumber plants.
Dilute nettle liquid 1:10. Spray cucumber plants if they are infected. Otherwise water it regularly. This strengthens the plants and makes them more resilient. In addition, the liquid manure also acts as a green cucumber fertilizer.
Sakhalin knotweed works as an infusion against cucumber powdery mildew. To do this, pour one liter of hot water over 10 g of dried leaves and let it steep for a few hours. Water and spray cucumber plants with it
A tried and tested secret recipe for many hobby gardeners against cucumber powdery mildew is this baking powder and rapeseed oil recipe:
- 50 grams of baking powder
- 50 milliliters of rapeseed oil
- some tropics detergent
- 5 liters of lukewarm water
Dissolve baking powder in 5 liters of lukewarm water and then add rapeseed oil and detergent. Preventively spray cucumber plants every 2 weeks over a period of 3 months in the evening.
Tips & Tricks
Grow cucumber plants again in the same location after 4 years at the earliest so that they do not become infected with fungi whose mycelium and spores overwinter in the soil!