Sunflowers bring a lot of color to the garden with their eye-catching, large and colorful flowers. Some varieties are particularly large, others delight us with a long flowering period. Unfortunately, powdery mildew infestation on sunflowers has increased significantly in recent years.
What does mildew look like on sunflowers?
When infected with powdery mildew, a whitish coating appears on thetop of the leaves, which looks like a layer of flour. In contrast, downy mildew appears as brownish spots on the leaves. A grayish fungal lawn forms on the underside of the leaf.
What causes powdery mildew on sunflowers?
Powdery mildew develops inwarm and dry summers. The fungal spores of this so-called “fair weather fungus” are spread by the wind. This means that sunflowers can quickly become infected with this disease. Downy mildew requires moisture to spread. This fungus is mainly spread to plants by splashing water from the soil. Infection is also possible via seeds or wind. Damp leaves that dry slowly are the perfect entry point for the pathogen.
How can I combat powdery mildew on sunflowers?
You can treat powdery mildew infestations very wellwith home remedies. You can spray the affected plants with a mixture of fresh milk and water or with a mixture of baking soda, rapeseed oil and water. Beforehand, you should remove all affected parts of the plants. Downy mildew damages sunflowers significantly more and is also more difficult to control. Since 1996, new breeds of this fungus have increasingly appeared in Europe. It is important to dispose of all affected plants immediately. Then spray the surrounding sunflowers with a garlic decoction.
How can I prevent powdery mildew on sunflowers?
Various care measures can prevent mildew disease:
- Avoid fertilizers containing nitrogen
- Consider the location requirements of the plants
- Use field horsetail tea as an additive to irrigation water
- Mulch the soil thickly
- Observe the correct plant spacing
- Never water on the leaves, but on the soil.
Because downy mildew is the most serious disease affecting sunflowers, prevention is particularly important.
Tip
Relocation after downy mildew
The spores of downy mildew overwinter on plant residues on the ground and directly in the soil. Downy mildew can survive there for up to eight years. Therefore, after a mildew infestation, make sure to find a new location for your plants in the following years.
