Problem: Black spot is a fungal disease commonly found on roses, but also on other flowers and fruits. While it doesn’t kill plants outright, it weakens them and makes them susceptible to other problems. In cool, moist weather, small black spots appear on foliage, which starts to turn yellow and eventually drops off.

Solution: The fungus overwinters in diseased canes and leaves, so remove both before winter. Keep foliage clean and dry by mulching beneath plants, positioning roses where morning sun will quickly evaporate dew, and watering at the roots rather than wetting the foliage. Consider planting varieties of roses resistant to black spot. Plants also can be sprayed with a fungicide to prevent black spot.

Along with diseases, pests can also cause problems.

Regards

Joseph Mareddy

Assistant Managing Editor

Journal of Plant Biochemistry and physiology