Bacterial disease that causes rapid blackening and dessication of blooms and foliage. Black, sunken twig and branch cankers develop later. Fire Blight causes twig dieback and blossom blight in up to 2-24 inches of twig length. The bacteria stays in the cankers over winter, and in the spring, oozes from the cankers and is carried by wind, rain and insects to healthy foliage. Avoid high nitrogen levels and excessive pruning.
Vigorous growth is much more susceptible to fire blight.
Prune four inches below visible cankers. Sterilize pruning equipment between cuts with one part household bleach to nine parts of water. Clean and oil equipment after pruning. Select fire blight resistant varieties and species. Contact the Extension office at 473-9600 for a list.