nysipm.cornell.edu 2019 Search for this title at the NYSIPM Publications collection: ecommons.cornell.edu/handle/1813/41246 Disease and Insect Resistant Ornamental Plants Mary Thurn, Elizabeth Lamb, and Brian Eshenaur New York State Integrated Pest Management Program, Cornell University Pyracantha Firethorn Pyracantha is a small genus of spiny evergreen shrubs in the rose family. White flowers are followed by a showy display of bright red, orange or yellow fruit which persist into fall and winter. Aside from their ornamental interest, the dense thorny growth habit provides a natural barrier and cover for wildlife. Like other members of the rose family, Pyracan- tha is susceptible to several diseases, including scab and fire blight. There are resistant cultivars and hybrids available. DISEASES Scab is a disease caused by the fungus Venturia inaequalis f.sp. pyracanthae, formerly known as Spilocaea pyracanthae (13). Perhaps the most important disease of Pyracantha, it occurs across the United States and Canada and is believed to have been imported from Europe. The disease spreads during rainy or humid weather. Infection is more common on fruit than leaves, and may result in premature leaf drop and blackening of the fruit. Scab Reference Species/Hybrids Cultivar Resistant Susceptible Pyracantha coccinea Government Red 13, 15 Kasan 2 Lalandei 2 Lalandei Monrovia 2 Prostrata 13 Runyanii 2 Pyracantha crenatoserrata 15 Pyracantha crenulata 15 Pyracantha koidzumii Bella 13 Bellii 15 Duval 13, 15 Scab Reference Species/Hybrids Cultivar Resistant Susceptible Pyracantha koidzumii San Jose 2 Santa Cruz 2, 3 Santa Cruz Prostrata 13, 15 ‘Cadvar' Silver Lining™ 3 Victory 2 Pyracantha rogersiana Flava 15 Pyracantha x Apache 2, 7 Dart's Red 2 Fiery Cascade 2, 11 Gnome® (‘Gnozam') 2 Golden Charmer 2 Gold Rush 2 Lowboy 2 Mohave 2, 3, 5 Navaho 2, 3, 6 Orange Charmer 2 Orange Glow 2 Pueblo 2, 8 Rutgers 2, 11 Saphyr Jaune™ (‘Cadaune') 2 Saphyr Orange™ (‘Cadange') 1, 2, 13 Saphyr Rouge™ (‘Cadrou') 1, 2, 13 San Jose 2 Santa Cruz 2 Shawnee 2, 4, 13, 15 Teton 2, 6 Victory 2 Fire Blight is a disease of Pyracantha and other plants in the rose family caused by the bacterium Erwinia amylovora. Named for the scorched appearance of affected leaves, blossoms and twigs, it can cause severe damage and death in nursery and landscape settings. Fire blight is favored by warm, humid weather, so it is especially prevalent in the Southeast. Insects and rain can spread the bacteria. Cultural practices that prolong succulent growth such as excess fertilization and heavy pruning can increase disease incidence and severity. Fire Blight Reference Species/Hybrids Cultivar Resistant Intermediate Susceptible Pyracantha atalantioides 14 Pyracantha coccinea 14 Fire Blight Reference Species/Hybrids Cultivar Resistant Intermediate Susceptible Pyracantha coccinea Runyanii 2 Sensation 13 Wyattii 2 Pyracantha koidzumii 13, 15 Pyracantha koidzumii Rosedale 2, 15 Santa Cruz Prostrata 13 Victory 15 Pyracantha rogersiana 14 Pyracantha rogersiana Flava 14 Pyracantha x Apache 2, 7 Dart's Red 2 Fiery Cascade 2, 11 Golden Charmer 14 Mohave 1, 2, 6 Navaho 2 Orange Charmer 14 Orange Column 14 Orange Glow 14 Pueblo 2, 8 Red Cushion 2 Red Elf 2, 11 Rosedale 2 Rutgers 2, 11 San Jose 13 Saphyr Jaune™ (‘Cadaune') 2 Saphyr Orange™ (‘Cadange') 1,2, 13 Saphyr Rouge™ (‘Cadrou') 1,2, 13 Shawnee 2, 4, 13 Soleil d'Or 14 Teton 2, 6 14 Yellow Charmer 14 INSECTS Hawthorn Lace Bug, Corythucha cydoniae, is a foliage feeding insect found throughout most of the US, southern Canada and northern Mexico (10). Many plants in the rose family are susceptible, but Pyracantha is a preferred host. Lace bugs feed on the underside of leaves creating small chlorotic spots visible mostly on the upper surface. Damage is unsightly and may spread to cover the entire leaf surface. Repeated infestations decrease plant vigor and may result in death of the plant. In a caged feeding study, researchers report P. atalantiodes ‘Aurea' was a less preferred host compared with P. coccinea ‘Orange Glow' and ‘Loboy', P. koidzumii ‘Ingleside Crimson', and P. angustifolia ‘Varie- gata' (12). Japanese Beetle, Popillia japonica, is a common foliage feeder of many landscape plants. Some resistance is reported for P. coccinea with only occasional feeding observed (9). REFERENCES 1. Cadic, A., J.P. Paulin, and J. Belin. 1990. New Pyracantha resistant to scab [Spilocaea pyracanthae (Otth.) Rostrup] and to fire blight [Erwinia amylovora (Burr.) Winsl. et al.]. Acta Hortic. 273:303­ 306. doi: 10.17660/ActaHortic.1990.273.44 2. Dirr, Michael A. 2009. Manual of Woody Landscape Plants: Their Identification, Ornamental Characteristics, Culture, Propagation and Uses. 6th ed. Stipes Publishing L.L.C., Champaign, IL. 3. Dirr, Michael A. 2011. Dirr's Encyclopedia of Trees & Shrubs. 1st Ed. Timber Press, Inc., Portland, OR. 4. Egolf, D.R. 1966. Pyracantha ‘Shawnee' [Rosaceae]. Baileya 14:61-63. 5. Egolf, D.R. 1970. Pyracantha ‘Mohave', a New Cultivar [Rosaceae]. Baileya 17:79-82. 6. Egolf, D.R. 1978. Pyracantha ‘Navaho' and ‘Teton'. HortScience 13:483-484. 7. Egolf, D.R. 1987. Pyracantha x ‘Apache'. HortScience 22:173-174. 8. Egolf, D.R. 1987. Pyracantha x ‘Pueblo'. HortScience 22:510-511. 9. Held, D. W. 2004. Relative susceptibility of woody landscape plants to Japanese beetle (Coleoptera: Scarabaeidae). J. Arboric. 30(6):328-335. 10. Johnson, W.T., and H.H. Lyon. 1991. Insects that Feed on Trees and Shrubs. 2nd Ed. Cornell Univ. Press, Ithaca, NY. 11. Molnar, T.J., and J.M. Capik. 2013. The Rutgers University woody ornamentals breeding program: Past, present, and future. Acta Hortic. 990, ISHS. doi: 10.17660/ActaHortic.2013.990.32 12. Schultz, P.B. 1983. Evaluation of hawthorn lace bug (Hemiptera: Tingadae) feeding preference on Cotoneaster and Pyracantha. Environ. Entomol. 12(6):1808-1810. doi: 10.1093/ee/12.6.1808 13. Sinclair, W., and H.H. Lyon. 2005. Diseases of Trees and Shrubs. 2nd Ed. Cornell Univ. Press, Ithaca, NY. 14. Teylingen, M. van. 2002. Ornamental hosts of Erwinia amylovora and the effect of fire blight con­ trol policy in the Netherlands. Acta Hortic. 590:81-87. doi: 10.17660/ActaHortic.2002.590.9 15. Vassey, W.E., C.J. Gould, and G.F. Ryan. 1977. Disease resistant pyracantha for the Pacific Northwest. Ornamentals Northwest 1(18):4-6. OTHER RESOURCES “Missouri Botanical Garden.” missouribotanicalgarden.org “Woody Plants Database” Urban Horticulture Institute, Cornell University. woodyplants.cals.cornell. edu/plant/search New York State Integrated Pest Management Cornell Cooperative Extension r Program Produced by the New York State Integrated Pest Management Program, which is funded through Cornell University, Cornell Cooperative Extension, the New York State Department of Agriculture and Markets, the New York State Department of Environmental Conservation, and USDA-NIFA. Design by Karen English, New York State IPM Program. Cornell Cooperative Extension provides equal program and employment opportunities. © 2019 Cornell University and the New York State IPM Program. Updated 3/2019. Search for this title at the NYSIPM Publications collection: ecommons.cornell.edu/handle/1813/41246 nysipm.cornell.edu.