Fire blight can strike trees and homeowners' wallets
WEST LAFAYETTE, Ind. - Homeowners with flowering pear trees should watch for signs of fire blight, a potentially devastating disease. And they should be just as vigilant in their watch for people who promise a quick remedy for the infection.
Arborists throughout the state are reporting hundreds of trees with fire blight, said Janna Beckerman, a Purdue University associate professor of botany and plant pathology. "I see it on many trees in my own neighborhood," she said.
Symptoms of fire blight are wilting shoots, cankers on branches and blackened leaves, which give the disease its name. "It literally looks like the tree has been scorched," Beckerman said. Trees are more susceptible to fire blight if a freeze occurs after blooming, such as what happened this spring.
Flowering pears and other ornamental fruit trees are popular in home landscaping. A single neighborhood may have more than 100 affected trees.
Beckerman warns homeowners to be on the lookout for disreputable people - whether a company calling on the telephone or someone just showing up on the doorstep - who claim that they can kill the disease-causing bacterium with chemical sprays or injections.
"Nothing can be done to halt the disease," Beckerman said. "It starts at the flowers and works its way down the branches. Trees can die if the infection reaches the main stem."
If fire blight affects only a few branches, it can often be successfully pruned, Beckerman said.
"Generally, homeowners can handle the pruning if it is just 1-2 branches," she said. "If it's more, they should consider contacting a certified arborist. Severely damaged trees may have to be removed."
Before pruning, homeowners should review steps outlined in Fire Blight on Fruit Trees in the Home Orchard, a Purdue Extension publication authored by Beckerman, because improper pruning can further damage the tree or spread the disease. The publication is available for free download from The Education Store at http://www.The-Education-Store.com
If trees have multiple strikes, or cankers, Beckerman said homeowners may want to put off pruning until winter when it's easier to prune and dispose of limbs. She encourages those who are considering new plantings or replacing diseased trees to select more fire-blight-resistant callery pear varieties, such as Cleveland Select, Bradford or Dancer, which is a different species of flowering pear (Pyrus betulifolia). Avoid the more susceptible Aristocrat variety.
There is another bacterial blight, called simply bacterial blight, which has similar symptoms to fire blight but is not as severe. Laboratory diagnosis is needed to differentiate the two.
Homeowners who have questions should contact the Purdue Plant and Pest Diagnostic Laboratory at 765-494-7071 or go to http://www.ppdl.purdue.edu
Writer: Olivia Maddox, 765-496-3207, firstname.lastname@example.org
Source: Janna Beckerman, 765-494-4628, email@example.com