Key points
- Scab is the most common disease of firethorns (Pyracantha spp.) in the landscape.
- The fungus Spilocea pyracanthae causes scab.
- This fungal pathogen survives the winter on infected twigs and leaves.
- The first symptoms appear in the spring as dark olive green to black lesions, sometimes sooty in appearance on leaves and crusty in appearance on twigs and fruit. Early disease symptoms also include yellowing of foliage.
- Severe disease outbreaks cause extensive premature leaf and fruit drop on highly susceptible cultivars.
Management
- The best options for disease management are to select resistant cultivars of firethorn. Firethorn cultivars resistant to both scab and fireblight include 'Apache', 'Fiery Cascade', 'Mohave','Navaho', 'Pueblo', 'Rutgers', 'Shawnee', and 'Teton'.
Rev. 2020