How to Prevent And Treat Common Rose Diseases and Pests

You can remove aphids from roses with a jet of water.

Many types of roses are susceptible to a variety of diseases and pests. Careful prevention and timely diagnosis and intervention are key to helping your roses stay healthy. Healthy roses require a good amount of care, but abundant and beautiful blooms repay your efforts.

Things You'll Need

• Garden hose
• Insecticidal soap
• Baking soda
• Fungicide
• Lime sulfur
• 3-in-1 fungicide/miticide/insecticide

Instructions

1. Spray small areas affected by aphids with a stream of water. Aphids, the No. 1 pest of roses, are small, green creatures that suck sap from the leaves, buds and stems of roses; aphids are particularly fond of new growth. For more serious cases, use insecticidal soap or insecticides. Follow the same treatment steps for mites, small imperceptible creatures that leave webbing, stippled leaves and leaf drop in their wake.

2. Water in the morning, keeping water off rose bush foliage, to avoid black spot, one of the most common rose diseases. Black and brown spots appear on leaves, with a growing ring of yellow gradually appearing around the dark spots, and the leaves eventually fall off. You can make a preventive spray with baking soda and water. Treat black spot with a fungicide. Follow the same preventive and treatment steps to address powdery mildew, another common rose disease that leaves white or grey spots on leaves and causes leaf drop.

3. Spray roses with lime sulfur or baking soda and water to check rust; in some cases you will need to resort to strong fungicides. Reddish-orange bumps, most often seen in damp, cool weather, that appear on leaves signals an invasion of rust.

4. Prevent thrips by spacing rose bushes so they have enough airflow between them. Remove spent blossoms quickly. Thrips are small yellow or black creatures that feed on rose flowers. Insecticides are often not helpful, so try spraying roses with water or insecticidal soap.

Tips & Warnings

• Keep a 3-in-1 fungicide/miticide/insecticide on hand to handle multiple rose pests.

References

• University of California IPM Online: Roses: Insect and Mite Pests and Beneficials
• University of Hawaii at Manoa College of Tropical Agriculture and Human Resources: Hawaii Pest and Disease Image Gallery (Miscellaneous Plants and Crops)
• Cornell University Department of Horticulture: Integrated Pest Management Of Roses