Here’s how to promptly treat powdery mildew when it appears on your roses.
Powdery mildew is a widespread fungal infection that infests the leaves, stems, and buds of roses in a dusty white powder. While it will not kill your roses, powdery mildew can weaken them and make them look repulsive if not treated promptly. This article describes how to spot, treat, and prevent powdery mildew on your roses.
What Is Powdery Mildew
Infected by several species of fungi, spores of powdery mildew spread via insects, wind, or rain splash. It is visible as white or grayish powdery patches on leaves and stems and increases as the fungus matures. The leaves infected by it may become yellow and fall off, retarding growth and reducing flowering.
Catch It Early
Early detection makes controlling powdery mildew much easier. Check your rose bushes weekly for white or gray spots, especially in warm, humid weather. Depending on your location, this vigilance might be needed throughout much of the growing season.
How to Get Rid of Powdery Mildew
Treat early with fungicides on healthy plant tissues to prevent the disease from spreading—no treatment will heal infected tissue. Remove and dispose of all infected leaves, stems, and flowers early. Treatment options are as follows:
Neem oil and horticultural oils: Organic pesticides sprayed to healthy tissues at first sight of mildew. Spray in the evening or on cloudy mornings to avoid leaf burn.
Sulfur: An old-type fungicide offered in dust or spray form that acts as a spore preventer from infecting plants.
Chemical fungicides: In case of severe infections, use powdery mildew-touted products and adhere to all precautions.
Avoiding Powdery Mildew
It is easier to avoid powdery mildew before it sets in compared to curing the disease after its occurrence. Fungi thrive in dark, humid, dense spaces. To avoid the disease:
Enhance air flow: Prune and space roses so that the center can open, reducing stale air and moisture buildup.
Avoid watering from above: Drip irrigation or soaker hoses can be employed to water at ground level without wetting leaves.
Give full sun: Roses need at least 6 hours of sun a day to evaporate leaves and inhibit mildew development.
Care for your roses: Well-watered, well-fertilized roses are more disease-resistant.
Remove infected areas rapidly: Remove diseased stems, leaves, and blossoms, and discard them in the trash (not compost) to avoid spreading spores. Clean pruners with alcohol after each cut.
Choose resistant varieties: Plant mildew-resistant rose types like Knock Out, rugosa, floribunda, or David Austin English roses.
By doing these, your roses will be healthy and powdery mildew-free.
