Symptoms and damage
disease is caused by the fungus Elsinoecorni, one of the most
common leaf diseases of flowering dogwoods. The flower bracts are usually
attacked first and then the leaves, young shoots and fruit of dogwoods, primarily
during wet spring weather. Symptoms are small (? inch), tan spots with
reddish-purple borders. When infection is severe, these spots can cause flower
bracts and leaves to become wrinkled and distorted. As further infections
occur, individual spots eventually merge to form larger spots. The centers may
drop out. This fungus survives from year to year on infected twigs, fruits and
COMMENTS on disease
rains or extended periods of high humidity are needed for disease development.
When dry weather follows bud swell and bloom, the symptoms are rarely seen on
the flower bracts. If spotting does not appear on the
bracts, the disease may not be severe on the leaves.
most cases this disease doesnt result in significant damage, but severe and
repeat infections each year can significantly weaken a tree. Thin the canopy to
increase air movement. Planting species and cultivars with some degree of
disease resistance is an excellent option for managing this problem in the
spotting becomes severe, fungicides can be used in the spring starting at bud
break and continuing until leaves are fully expanded. Fungicides available for
use include chlorothalonil, mancozeb, propiconazole, thiophanate-methyl or
copper fungicides .