All rights reserved.
Roses are vulnerable to many diseases.
Fortunately, few of these diseases are common in Minnesota. Black spot, powdery mildew, and Botrytis blight may afflict Minnesota's roses. Other diseases in the state are rust, cankers, crown gall, wilt, and viruses. Black Spot is caused by the fungus Diplocarpon rosae . The disease can cause almost complete defoliation of bushes by early fall.