Controlling Fire Blight on Photinia

Preventive Control

• Providing optimal care to photinias helps ensure the growth of healthy, disease-free plants. Grow red tips in areas of the home garden that offer full-sun exposure. For best development, maintain moist, well-drained soil high in organic content; this shrub tolerates drought and salt as well as acidic to slightly alkaline pH levels. Always plant a photinia that grows best in your region. For example, the Fraser photinia (Photinia x fraseri) grows best in U.S. Department of Agriculture plant hardiness zones 7b through 9b while the red-leaf photinia (Photinia glabra) performs best in USDA zones 7a through 11.

Disease

• Fire blight is a bacterial disease that affects photinia as well as other host plants, such as fruit trees. Caused by the bacterial pathogen Erwinia amylovora, fire blight disease spreads on wind and in splashing water and invades plants through natural openings including wounds. The disease typically appears during moist, warm spring weather. Fire blight begins with the development of oozing cankers and wet, dying plant bark. As the disease progresses, flowers and stems take on a scorched appearance, as though burned by fire, often leading to plant death.

Cultural Solutions

• Because weather is a significant factor in disease growth, prevent and approach fire blight problems by first focusing on cultural solutions. For example, avoid irrigating photinia during warm weather to avoid creating the moist conditions necessary for disease proliferation. In addition, skip the desire to prune or add nitrogen fertilizer to soil, as this causes the quick development of new plant tissue, which is the most susceptible to fire blight disease. Remove and destroy areas affected by disease during winter or summer to avoid spreading infection.

Advanced Control

• While there is no cure for fire blight, chemical control in conjunction with cultural control offers some management of this disease on photinia plants. Apply a copper-based fungicide, such as Bordeaux mixture to your photinia as blossoms open to fight infections, suggests the University of California Statewide Integrated Pest Management Program. Only apply the copper fungicide if temperatures remain above 60 degrees Fahrenheit, once every five days, until bloom is complete. To create Bordeaux mixture, mix copper sulfate, lime and water in a 10-10-100 ratio, including 3-1/3 tablespoons of copper sulfate and 10 tablespoons of dry hydrated lime mixed into 1 gallon of water. Combine the mixture in a hand sprayer or spray tank. Apply the mixture to your photinia immediately, saturating the entire plant.