The Mr. Lincoln rose, scientifically named Rosa "Mister Lincoln," gets its name from Abraham Lincoln, the 16th president of the United States. It boasts velvety red, urn-shaped buds with intense fragrance. Mr. Lincoln roses grow to be 3 to 5 feet tall and typically bloom from summer to fall. Their long, strong stems make them a popular cut flower. Mr. Lincoln roses are susceptible to the same pesky diseases as most other types of roses.
Leaf rust comes from a fungus that produces a powdery residue, usually on the undersides of leaves. It can appear in different colors and may be orange, brown, yellow and even purple. Leaf rust can cause distortion of the leaves and it can cause your rose to defoliate. If you notice leaf rust, remove all of the affected leaves. Be sure to get rid of any infected leaf debris at the base of the rose. Although this disease can make your plant's foliage look unattractive, it usually poses no major threat to the overall health of your rose.
Botrytis blight, sometimes referred to as gray mold, is a very common disease among roses. It is caused by the fungus species Botrytis cinerea, which is particularly favorable of the cool, wet weather of spring and early summer. It is markedly worse during rainy spells. According to the Cornell University botrytis blight fact sheet, this disease causes parts of the rose to look brown or spotted. Silver-gray spores may appear and, if the rose is seriously infected, the spores may appear as dust coming off the plant. The best measure for controlling the infestation of botrytis blight is plant inspection. Check your rose regularly and remove any brown or blighted leaves. Avoid overhead watering, as this can exacerbate the problem. Always water the base of the rose.
According to the Colorado State University Extension, this disease is one of the most common and easily recognized plant diseases. Powdery mildew thrives in warm, dry areas with poor air circulation. The visible signs of powdery mildew are patches or spots of a powdery growth on the upper sides of leaves. The mildew can be white or gray, with pinhead-sized, circular formations. It causes foliage yellowing and leaf drop and can cause budding roses to fail to open. Control this disease by removing any infected leaves and flowers. As with botrytis blight, avoid overhead watering, which creates a breeding ground for further disease.