Karen Rane, Plant Disease Diagnostician, Dept. of Botany & Plant Pathology, Purdue University
Pyracantha, also known as firethorn, is an ornamental shrub known for its sharp thorns as well as its attractive red, orange or yellow fruit. A common fungal disease called scab can result in significant damage to leaves and fruit. The fungus, Spilocaea pyracanthae, causes black spots on leaves and twigs, but the most obvious symptoms are found on the fruit (see figure). Infected fruit are covered with dark lesions, and in severe infections the fruit may drop prematurely. Like most fungal diseases, scab infection is favored by films of moisture on plant surfaces, so overhead sprinkler irrigation that comes in contact with the foliage and fruit will help to spread the disease. Several Pyracantha cultivars, such as “Fiery Cascade”,, “Rutgers”, “Mohave” and P. coccinea cv. “Prostrata”, are considered to be resistant to scab.
Scab on Pyracantha
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