Fire blight, found across North America, is a disease to be reckoned with. Caused by the bacterium Erwinia amylovora, this blight affects:
- Cane fruits.
The disease is most likely to appear after a mild winter and during a wet spring. Insects transport fire blight bacteria from plant to plant when the hosts are flowering.
- Brown leaves with a singed appearance.
- Dead leaves clinging to tree instead of falling.
- Shoots curled downward, similar to a shepherd’s crook (see photo below).
- Amber droplets on shoots.
- Sudden shoot death.
- Wet, oozing bark.
- Fruit death.
- Rapid plant death.
Unfortunately, there is no effective cure for fire blight once it strikes. The best option is to cut down and burn the affected tree, bush, or canes to avoid the spread of the disease.
If you want to make an attempt to save a valuable fruit tree, you will have to prune heavily, but cautiously. Choose a dry day to work so that bacteria spread is minimized. Cut off blighted twigs and branches at least 12 inches below the sites of decay. Collect the infected wood in a plastic bag to be burned when you are finished. Sterilize your pruning tools between each cut with a strong bleach solution.
Because pears are extremely susceptible to fire blight, growing pears on a large scale is not advised in Kansas. While you may be able to grow a few pear trees, doing so will make growing apples very difficult because of the increased disease risk. If apples are your priority, destroy all pear trees in the vicinity.
To further prevent fire blight in your orchard:
- Select plant varieties resistant to the disease.
- Avoid weakening the tree through excessive pruning.
- Spray trees and canes with copper or white vinegar in the spring.
- Keep insects in check.
- Avoid the use of high-nitrogen fertilizer, which encourages the rapid growth of soft, disease-prone tissue.