The Canada red chokecherry, a member of the rose family, is susceptible to several diseases, some of which can cause permanent injury. This colorful tree produces an oval canopy of light green foliage that changes to showy hues of purple and red in the fall. The red chokecherry is a tolerant tree that thrives in full to partially shaded locations.
X-disease is a debilitating disease caused by a parasitic organism that thrives in the tree. Leafhoppers transport it from infected trees to healthy ones. The infected chokecherry experiences leaf curl, droop, wilt, discoloration and loss of vigor. X-disease also uses the chokecherry as a reservoir in an effort to infect surrounding chokecherries and other trees. There is no cure for X-disease, although inoculations can slow the chokecherry’s symptoms. It is best to remove and destroy infected trees to reduce the potential of cross-infections. Owners should also spray the area with an insecticide to reduce the presence of leafhoppers.
Black knot infections are the most aggressive after the growing season’s cool, wet period. This spore-borne fungal disease travels by wind and rain onto the chokecherry and enters the tree’s system via its wounds. The infected area develops light-colored growths that age into hard, dark-colored cankers. During severe infections, the cankers girdle the infected branches and stems, causing die-back and wilt of the areas. Prune the infected branches and stems to control the disease, which also prevents the possibility of cross-infections that are caused by the fungal spores that reside within the cankers. Fungicidal spray treatments are also effective when combined with pruning.
Shothole is a bacterial foliage disease that can quickly disfigure the chokecherry. The infected foliage develops bacterial spots and holes before the leaves decay. The spots are enhanced by a purplish-brown color as the rest of the leaves take on a much lighter, almost yellow, appearance. Chemical treatments and cures are available, so speak with your local horticultural or nursery specialist for treatment assistance.
Also known as perennial canker, Valsa canker is a causal fungal disease that can only infect the chokecherry through its wounds and cracks. The infection causes the chokecherry to develop sunken cankers on its woody areas that eventually girdle and kill the tree. To eliminate the disease, remove the chokecherry’s infected areas with sharp, sterile shears, then treat the pruned tree with a fungicidal spray. However, remove and destroy severely infected chokecherry trees since treatment is futile.