murphy4trees
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Any suggestions... I've got 3 fairly stresses red/black oaks in my backyard that are hugely important to keep the house and yard shaded and cool.
God Bless All,
Daniel
Dual threats scorching life out of oaks
A disease is killing 39% in N.J., a survey says.
The Pa. rate may be 30%. Drought has worsened the impact.
Kaitlin Gurney INQUIRER SUBURBAN STAFF
From the azalea garden at the Philadelphia Museum of Art to Moorestown's stately tree-lined streets, a mysterious scourge known as bacterial leaf scorch is spreading through the region's oak population, dooming the shade trees to a slow death.
Four years of drought conditions have exacerbated the effects of leaf scorch, making this an excruciating year for the region's trees, according to area experts.
The incurable insect-borne disease, which has decimated main streets and city parks from the Carolinas to Connecticut, first hit Southeastern Pennsylvania and New Jersey in the late 1980s. The mottled brown leaves that characterize the disease mar fall foliage and leave homeowners with the choice of pricey antibiotic treatments to stave off a tree's death or even more expensive uprooting.
In an effort to determine the severity of the disease, the New Jersey Forest Service tested 1,372 oaks throughout the Garden State last year. The results released this month showed that 533 oaks, or 39 percent of those tested, were infected. More than half of the infected trees were in South Jersey, the study showed.
While Pennsylvania has yet to quantify the impact on its oaks, local arborists estimate that 20 percent to 30 percent of the red, pin and black oaks in the area are dying of the disease. Marilyn Romenesko, who cares for the azalea garden at the Art Museum for a program of the Pennsylvania Horticultural Society, said all the red oaks and many of the black oaks at the ornamental garden had been infected.
Oaks have been a particular concern for Moorestown, where the disease was first detected in New Jersey. Many of the 300 trees removed in the township in the last three years have been afflicted with bacterial leaf scorch.
"When you start to look for it, you'll realize this disease is everywhere," said Ann Gould, a plant pathologist at Rutgers University in New Brunswick, N.J. "Oaks all over the region are in a slow pattern of decline."
Researchers say this is the latest plague to affect the region's beleaguered and drought-stricken forests, which have suffered chestnut blight and Dutch elm disease in recent decades. But unlike those two quick-killing diseases, bacterial leaf scorch sometimes takes 10 years to kill a tree.
The disease is most visible in early fall, when characteristic yellow and red bands divide the brown tips of the leaves from their green centers.
Leafhoppers, treehoppers and spittlebugs spread Xylella fastidiosa, the bacterium that causes leaf scorch, when they feed on tree leaves, but scientists are unsure exactly which species are responsible for the transmission. Insecticides are ineffective, they say.
As the bacteria multiply, they clog more of the veins that transport water to the tree's branches, causing whole sections of the tree to wither.
Other shade trees, such as sycamores, elms, maples and sweet gums, may also come down with bacterial leaf scorch. White oaks, which have rounded leaves, are less susceptible to the disease than red oaks and their pointy leaves, Romenesko said.
The only salve for an infected tree is temporary and expensive - an injection of the antibiotic oxytetracycline. The treatment will kill the bacteria and halt the disease's course for about a year, when the treatment is required again.
An antibiotic injection for a 60-year-old tree with a three-foot diameter costs about $250, said Ken LeRoy, an arborist with McFarland Tree & Landscape Services in the Germantown section of Philadelphia.
That treatment is cost-prohibitive for sites such as the University of Pennsylvania's Morris Arboretum in Northwest Philadelphia, which has 13,000 plants on its 170 acres, according to the arboretum's horticulture director, Anthony Aiello. Watering, mulching and pruning affected trees also stave off the effects of the disease, he said.
Removal of a dying, 60-year-old oak costs about $2,000, LeRoy said.
Leaf scorch "is here to stay," he said. "The trees need to learn to live with it, or they're going to be dying of it."
Because the symptoms of bacterial leaf scorch are similar to that of general drought stress, researchers caution homeowners to have their trees tested for the disease before they embark on the expensive antibiotic treatments, said Jerome Frecon, the agricultural agent in Gloucester County.
"If you see part of the tree that's brown, that's likely leaf scorch. But if a tree is uniformly brown, the leaves have probably just withered from the drought," he said.
Some arborists, such as Hal Rosner of Bartlett Tree Experts in Bala Cynwyd, said the number of trees dying this year was overwhelming - and depressing.
But LeRoy said it was important to replant and keep the urban forest growing.
"We've been dealt some terrible blows, but it's important to keep planting," he said. "Smaller trees, like dogwoods or pears, just don't have the effect of a towering oak or a maple."
Contact Kaitlin Gurney at 856-779-3910 or [email protected].
Any suggestions... I've got 3 fairly stresses red/black oaks in my backyard that are hugely important to keep the house and yard shaded and cool.
God Bless All,
Daniel
Dual threats scorching life out of oaks
A disease is killing 39% in N.J., a survey says.
The Pa. rate may be 30%. Drought has worsened the impact.
Kaitlin Gurney INQUIRER SUBURBAN STAFF
From the azalea garden at the Philadelphia Museum of Art to Moorestown's stately tree-lined streets, a mysterious scourge known as bacterial leaf scorch is spreading through the region's oak population, dooming the shade trees to a slow death.
Four years of drought conditions have exacerbated the effects of leaf scorch, making this an excruciating year for the region's trees, according to area experts.
The incurable insect-borne disease, which has decimated main streets and city parks from the Carolinas to Connecticut, first hit Southeastern Pennsylvania and New Jersey in the late 1980s. The mottled brown leaves that characterize the disease mar fall foliage and leave homeowners with the choice of pricey antibiotic treatments to stave off a tree's death or even more expensive uprooting.
In an effort to determine the severity of the disease, the New Jersey Forest Service tested 1,372 oaks throughout the Garden State last year. The results released this month showed that 533 oaks, or 39 percent of those tested, were infected. More than half of the infected trees were in South Jersey, the study showed.
While Pennsylvania has yet to quantify the impact on its oaks, local arborists estimate that 20 percent to 30 percent of the red, pin and black oaks in the area are dying of the disease. Marilyn Romenesko, who cares for the azalea garden at the Art Museum for a program of the Pennsylvania Horticultural Society, said all the red oaks and many of the black oaks at the ornamental garden had been infected.
Oaks have been a particular concern for Moorestown, where the disease was first detected in New Jersey. Many of the 300 trees removed in the township in the last three years have been afflicted with bacterial leaf scorch.
"When you start to look for it, you'll realize this disease is everywhere," said Ann Gould, a plant pathologist at Rutgers University in New Brunswick, N.J. "Oaks all over the region are in a slow pattern of decline."
Researchers say this is the latest plague to affect the region's beleaguered and drought-stricken forests, which have suffered chestnut blight and Dutch elm disease in recent decades. But unlike those two quick-killing diseases, bacterial leaf scorch sometimes takes 10 years to kill a tree.
The disease is most visible in early fall, when characteristic yellow and red bands divide the brown tips of the leaves from their green centers.
Leafhoppers, treehoppers and spittlebugs spread Xylella fastidiosa, the bacterium that causes leaf scorch, when they feed on tree leaves, but scientists are unsure exactly which species are responsible for the transmission. Insecticides are ineffective, they say.
As the bacteria multiply, they clog more of the veins that transport water to the tree's branches, causing whole sections of the tree to wither.
Other shade trees, such as sycamores, elms, maples and sweet gums, may also come down with bacterial leaf scorch. White oaks, which have rounded leaves, are less susceptible to the disease than red oaks and their pointy leaves, Romenesko said.
The only salve for an infected tree is temporary and expensive - an injection of the antibiotic oxytetracycline. The treatment will kill the bacteria and halt the disease's course for about a year, when the treatment is required again.
An antibiotic injection for a 60-year-old tree with a three-foot diameter costs about $250, said Ken LeRoy, an arborist with McFarland Tree & Landscape Services in the Germantown section of Philadelphia.
That treatment is cost-prohibitive for sites such as the University of Pennsylvania's Morris Arboretum in Northwest Philadelphia, which has 13,000 plants on its 170 acres, according to the arboretum's horticulture director, Anthony Aiello. Watering, mulching and pruning affected trees also stave off the effects of the disease, he said.
Removal of a dying, 60-year-old oak costs about $2,000, LeRoy said.
Leaf scorch "is here to stay," he said. "The trees need to learn to live with it, or they're going to be dying of it."
Because the symptoms of bacterial leaf scorch are similar to that of general drought stress, researchers caution homeowners to have their trees tested for the disease before they embark on the expensive antibiotic treatments, said Jerome Frecon, the agricultural agent in Gloucester County.
"If you see part of the tree that's brown, that's likely leaf scorch. But if a tree is uniformly brown, the leaves have probably just withered from the drought," he said.
Some arborists, such as Hal Rosner of Bartlett Tree Experts in Bala Cynwyd, said the number of trees dying this year was overwhelming - and depressing.
But LeRoy said it was important to replant and keep the urban forest growing.
"We've been dealt some terrible blows, but it's important to keep planting," he said. "Smaller trees, like dogwoods or pears, just don't have the effect of a towering oak or a maple."
Contact Kaitlin Gurney at 856-779-3910 or [email protected].
