Roses in the garden can be infected with a variety of bacteria, fungi, and viruses, leading to diseases like powdery mildew and rust. Roses may also be damaged by nutrient deficiencies and other environmental problems.
Our Pest Notes: Roses: Diseases and Disorders was recently updated by University of California experts John Karlik, Deborah Golino, and Maher Al Rwahnih. This free publication provides an integrated approach to managing rose problems that includes careful variety choice, proper irrigation, correct pruning, and sanitation. Although some rose enthusiasts might consider regular application of fungicides a necessary component of rose care, many gardeners can grow plants with little to no use of fungicide.
Rose leaves infected by rose rust. (Credit: Jack Kelly Clark)
This updated Pest Notes includes additional details about the biology and management of downy mildew and anthracnose, as well as information about emerging viral diseases. The authors also added new photos, references, and an updated list of fungicides.