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.
--Karen Rane, Plant Disease Diagnostician, Dept. of Botany & Plant
Pathology, Purdue University |
Scab on Pyracantha
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