Fire Blight on Ornamental Pears
February is here and we are fast approaching spring. Most of us are working hard to reach our new year goals. We may even be planning big things, such as Valentine’s day. This time of year, couldn’t be busier for families with school and extracurricular activities. In the midst of all of this busyness, Fannin Tree Farm wants to remind you to think about your trees.
In the month of February, some trees are preparing to bloom. Buds are swelling in preparation for spring. Ornamental Pears, which include Bradford, Cleveland, and Aristocrat Pears to name a few, are ready to flower. Around the third week of February, these pears will provide a floral display that is not easily match, especially for the time of year.
This display is short-lived, approximately 3-to-4 weeks long. While it is when the tree is most beautiful, it is also when the tree is most vulnerable. A bacterium referred to as Fire Blight (Erwinia amylovora) often infects the tree by entering the blooms. This floral infection is very destructive as it develops throughout the tree.
Luckily, there are management practices that have been demonstrated to be effective in suppressing these infections. Our best method for preventing Fire Blight is sanitation pruning.
At Fannin Tree Farm we use Lysol to clean our tools after removing infected plant parts. This reduces the inoculum and prevents further disease spread throughout different parts of the tree.
We also provide weekly spray treatments using antibiotics and bactericides. These treatments are very effective if applied weekly, during the flowering period.
After it’s all said and done, the flowers are gone, an untreated flowering pear, may now be infected. This pathogen over-winters, in canker sites on branches throughout the crown. It is spread by splashing water and facilitated by pollinating insects, such as honey bees. Time will tell if an untreated tree is infected.
In the late spring, early summer, an infected tree should show signs of this disease. Brown, blighted shoot tips will wilt rapidly. This blighted shoot is referred to as, “shepherd’s crook.” At the beginning of the disease development, leaves on the diseased shoots show a blackening along the midrib and veins.
Later, as the disease progresses in the plant, it develops in the water conducting tissue. The bacterium multiplies, reducing the translocation of water and nutrients, and causes cracks in the bark that appear to be sunken on the surface. An amber-colored bacterial ooze may be identified on the bark. A brown-to-black discoloration of the wood beneath the bark may help identify the disease.
You may ask, can an infected tree still be managed? The answer depends on the severity of the infection. A young, healthier, flowering pear may be able to live with this disease for a few years. While an older tree may see rapid decline.
We always recommend sanitation pruning to prevent the disease spread. Appropriate amounts of fertilizer will help the plant maintain vigorous growth and prevent susceptibility to branch cankers. Other treatments using antibiotics and bactericides have been demonstrated to suppress the expression of the disease. We recommend spray applications during the blooming period, but sometimes micro injection through the root flare, or lower trunk may be necessary.
The best way to manage this disease is through prevention. The best time to develop a plan is now. If you would like a free consultation with one of our Certified Arborist, please contact us today at 972-747-9233.