Orange Fungus in a Rose
- Rust fungus displays as small, bright orange dots on the undersides of rose leaves. Other symptoms include dried, yellowing leaves and raised wart-like formations on the tops of leaves. This fungus thrives in cool, misty conditions, appears in the spring and fall and travels from one bush to the next via insects and wind-borne spores. The fungus eventually kills leaves and defoliates entire plants.
- Spray rust-infected roses with fungicide to prevent the disease from spreading; you cannot save infected foliage, but you can prevent widespread damage. Prune and throw away infected foliage to minimize spreading; don't add it to the compost pile, as you'll spread the fungus. Prune and clean up the garden in fall to keep rust spores from overwintering in the garden.
- Prevent and minimize rust fungal infections with correct planting and maintenance care. Plant roses with 2 to 4 feet of space to give each rosebush room for sun and air circulation. Sun and air both dry the roses out to prevent fungal infections, and roses are less likely to share diseases when they're given generous spacing. Water roses in the morning to allow them to dry completely before nightfall; roses are more susceptible to fungus if they remain damp overnight.
- Healthy, thriving roses lose their leaves during a rust infection, but they should survive and recover. Maintain your roses with rich organic compost amendments, regular feedings, weekly waterings and mulch to keep them healthy. Prune off dead and damaged foliage to encourage quick recovery and new foliage growth. Prune roses back in February to maintain their shape and healthy growth.