First symptoms of apple scab (Venturia inaequalis) are dark green leaf spots in spring that spread to gray-brown fungal lawn. In summer, brown, sunken, unappetizing scabs spoil the ripening apples. Don't let the most common apple tree disease spoil your appetite. These tips reveal how you can fight scab fungi without poison.
How to fight apple scab without poison?
Apple scab can be controlled biologically by making horsetail decoction and spraying it on infected apple trees. Preventive measures include removing fallen leaves, regular watering with nettle manure, fruit tree pruning for better ventilation, mulching and supporting compost worms.
Organic spray horsetail decoction combats apple scab
Sprays with horsetail decoction create a natural protective film containing silica on leaves and fruits. In this way, scab fungus spores do not find any attack surface on the plant tissue. In contrast to chemical fungicides or wet sulfur, you can use the organic spray to specifically combat apple scab in harmony with nature. The following instructions explain how to make horsetail decoction yourself and use it correctly:
Recipe
- Collect 1 kg of field horsetail (Equisetum arvense), chop it up and put it in a vat
- Pour 10 liters of water over it, preferably collected rainwater
- Stir in 2 handfuls of stone flour (€13.00 on Amazon)
- Cover the container with a jute sack or used curtain
- Set up in a sunny, warm location
- Stir daily for 14 days
- Sift the horsetail broth, dispose of the fermented residue in the compost
Application
Please dilute the highly concentrated horsetail decoction with water in a ratio of 1:5. The organic spray is now ready for use. The highest risk of infection occurs between leaf emergence and the end of the flowering period. Spray the apple tree crown with the decoction once a week.
A second time window with an increased risk of infection opens six to eight weeks before the harvest. Repeat the control with horsetail decoction to prevent the larger summer apple scab spores from spreading on the fruit peel.
Preventing apple scab – tips & tricks
Fighting apple scab in the home garden is not a sprint, but a marathon. By taking effective preventative measures every year, you will sustainably increase the effect of horsetail decoction. The following tips list tried-and-tested precautions against nasty apple scab in the hobby garden:
- Remove fallen leaves and autumn leaves promptly (most dangerous source of infection)
- Water apple trees regularly with nettle manure
- Cut fruit trees every year for a light-flooded crown
- Create a large tree disc and mulch it with compost or withered grass clippings
- Underplant apple trees with garlic and chives
Penetrant scab fungi have a bad hand if the garden is richly populated with compost worms and their own species. Scientists found that the fungal spores in the intestinal tract are destroyed by earthworms.
Tip
Note apple scab-resistant varieties in the planting plan if you start your own apple orchard. Recommended premium varieties are Retina, Rubinola and Topaz. Among the classics, Boskoop, Jonagold and Cox Orange are well equipped to combat scab fungi in sunny, airy locations.