We have a large amount of Bradford pears in the county, and many are concentrated to subdivisions. They create shade and look great in the spring with their white flowers. This year they may have more issues with a certain disease than in the past. This disease is Fire Blight and can also spread to fruiting pears, apples and crabapple.
Initially the disease often enters the tree through natural openings, especially flowers and wounds in the spring. Once established in the tree, fireblight quickly invades through the current season’s growth into older growth.
Fireblight can be spread from diseased to healthy plants by rain, wind, and pruning tools. The bacterium can survive the winter in sunken cankers on infected branches. In spring, the bacteria ooze out of the cankers and attract bees and other insects. Insects also help spread the disease to healthy plants. The bacteria spread rapidly through the plant tissue in warm temperatures (65 degrees F or higher) and humid weather.
During spring and summer, prune out infected branches 8 inches below the damage. Avoid pruning when the plants are wet. Dip pruning tools in 70 percent isopropyl alcohol (rubbing alcohol) or 10 percent bleach solution (one part bleach to nine parts water solution) between each cut. Wash and oil shears when you are finished. These practices avoid spreading the pathogen.
Avoid heavy nitrogen fertilization, especially in summer, when succulent growth is most susceptible to fireblight infection. Avoid splashing water. Chemical control is not always effective and needs to be applied preventively. Therefore, in years when warm, humid, wet weather coincides with flowering and leaf emergence, spray plants with a fungicide containing basic copper sulfate (Kocide) or an antibiotic (Agrimycin) to reduce infection. Applications of Agrimycin need to begin at the start of blooming and continue every three-to-four days during the bloom period. Application of Kocide should begin at bloom and continue every seven days during bloom. Re-application following rain may be needed.
For more information or questions, contact Effingham Ag Agent Sam Ingram at 754-8040 or firstname.lastname@example.org