Roses Roses Blackspot on Roses One of the three major diseases that affect roses is Blackspot First signs are black pinhead size dots on rose leaves. Regular treatments for large outbreaks.
Prevention involves a solution of one part lime to nine parts wettable sulfur.
Spray this during the winter Remove infected leaves immediately. For large infestations weekly applications of a fungicide If you have a tip for handling Black spot or a anything to do with growing roses here in our northern climate. Let us know. Compendium of Rose Diseases By R. Kenneth Horst Diseases caused by fungi, bacteria, viruses, and nematodes are presented in pictorial and descriptive form. More than 80 color photographs aid pathogen identification.