The statement that the most common foliar disease of roses in Kansas is Black Spot is true.

• A. True
• B. False
• C. Not Sure
• D. Cannot Be Determined

Answer: (A)

Black spot is the most common foliar disease on roses in Kansas because the pathogen overwinters in fallen leaves and is repeatedly triggered each spring by regular leaf wetness from rain and typical spring temperatures. This combination—inoculum in leaf litter and frequent moisture on leaves—creates ideal conditions for Diplocarpon rosae to infect and spread, making black spot occur year after year in many Kansas roses. The disease presents as small, dark spots on leaves with yellow halos, leading to yellowing and leaf drop, which is a familiar pattern for many growers in the region. Because these conditions are so common in Kansas’ climate, black spot tends to be more prevalent than other foliar diseases like powdery mildew or rust. Effective management focuses on reducing sources of inoculum and improving leaf conditions: remove and destroy infected leaves, improve air circulation around plants, water at the base to avoid wetting foliage, and apply preventive fungicides as needed, especially on susceptible varieties.