Disease invades Durham’s Bradford Pear trees

Jun. 18, 2014 @ 02:33 PM

Thousands of Bradford Pear trees in Durham are sick, but the treatment could be worse than death.

That’s because pruning and pesticides are expensive and don’t guarantee success, which means the best move is often to send the victim to tree heaven, according to Michelle Wallace, consumer horticulture agent for Durham County.
Wallace has been slammed recently with calls from Durham residents and homeowner associations about what’s sickening their Bradford Pear trees.
“The answer is simple, but the solution is not,” she said.
Two problems have made this one of the worst years in memory for Bradford Pears in Durham, she said.
One is fire blight, a bacterial disease spread mainly by flies when the tree is in bloom. Symptoms include persistent dead leaves, stems and branches.
Careful inspection shows sunken cankers that exude a milky-white ooze containing millions of bacteria, which can be spread by wind, rain and pruning.
“Unfortunately, there is no silver bullet,” she said, although the disease can sometimes be pruned out of the tree.
Wallace recommends pruning eight inches below the infected area and removing the dead and diseased wood, but that can be costly and time-consuming, she said. Even with pruning, the tree can become diseased the following year when it’s in bloom.
A second step, which Wallace does not recommend, is spraying the tree with an antibiotic pesticide, which only works when the plant is in bloom.
“I generally don’t recommend that homeowners spray because of the risks involved and the overall cost,” she said. “You can put a lot of time and money into saving this tree and it can split after a bad storm.”
Wallace suggests replacing the tree, which she said will save money and time in the long run.
Bradfords also are being hit with another disease called cedar-quince rust, a fungus that appears on the fruit and looks like orange-pink spores. But Wallace said the fruit is ornamental and not worth treating.
One Durham resident who has a seriously ill Bradford Pear tree is Anthony Evans, who lives in the northern Durham subdivision of Horton Hills.
Evans said the tree, which he’s had for 17 years, was healthy until this year, when its leaves turned brown and fell to the ground. Other neighbors are having the same problem.
“It’s very disappointing, because we’ve got a healthy collection of foliage in our yard,” he said.
Evans said he and his wife are considering removing the tree, because treatment would be so costly.
Alexander Johnson, Durham’s urban forestry manager, believes Bradfords are a nuisance.
“I’m opinionated about Bradford Pears,” he said. “I think they’re a terrible tree, and I wish people had never planted them. The fact that they’re dying, I’m perfectly happy with.”
Johnson said Bradfords “self-destruct” after a period of years.
“They’re weak-wooded,” he said. “They’re heavy, and they’ve got poor form that’s prone to failure. On the other hand, they grow very quickly; they establish effectively and are drought-tolerant.”
Because of those attributes, he said, people embraced Bradfords and overplanted them.
During tree-damaging storms, it’s the Bradford that’s most likely to fall into the road.
“If I get a call at 2 a.m. to get a tree out of the road, nine times out of 10 it’s a Bradford Pear,” he said. “They don’t handle wind or ice. They’re just a nuisance.”
For those who opt to remove their Bradford Pears and want a replacement, Wallace suggests these tree options:
Cercis canadensis species (redbuds)
Chionanthus species (fringe trees)
Lagerstroemia species (crape myrtles)
Cornus kousa  (Kousa dogwood)
Halesia carolina  (Carolina silverbell)
Magnolia soulandeana (saucer magnolia)
Oxydendrum arboretum (sourwood)

For information on fire blight and cedar-quince rust, go to http://durhammastergardeners.wordpress.com/tag/quince-rust/ or contact a Durham County Extension master gardener at 919-560-0528 or send email to mastergardener@dconc.gov .