Tree Diseases
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OaksSudden Oak Death (currently west coast)Sudden Oak Death California Oak Mortality Task Force
Leaf ScorchDISEASE IMPERILING OAK TREES THE MID-ATLANTIC IS ONE REGION WHERE BACTERIAL LEAF SCORCH IS SPREADING. By Walter F. Naedele, Inquirer Staff Writer As the area's maple trees delight in their seasonal crimson and gold colors, some of the region's oak trees are wearing drab brown. Autumn alone isn't the cause. The trees are infected with bacterial leaf scorch, a deadly disease that is endangering thousands of red oaks and pin oaks in Mid-Atlantic states. The disease is carried by insects that inject bacteria into twigs, clogging veins that carry nutrients from roots to leaves, killing them and eventually tree limbs. It has been found in Philadelphia and its suburbs - from Independence Mall to Wilmington to the heavily shaded streets of Moorestown. That is because the oak is one of the few tree species hardy enough to survive tough urban and other streetside conditions. Experts were unsure whether trees in forests are affected, because oaks also suffer from a fungus-related disease that causes similar leaf deterioration. Leaf scorch "didn't seem like it was going to be a huge problem until last year," said Ann Gould, a specialist in the plant pathology department of Rutgers University. "Last year, we got a lot of reports about it, thinking it was related to the drought. This year," she said, "we've gotten lots and lots of reports." For a long time, Gould said, dying oaks were clustered "in certain hot spots - Camden, Salem, Burlington and Gloucester Counties." In some towns, she estimated, "30 percent of the mature landscape oaks . . . were affected." But this year, the pathologist said, she has found the disease everywhere she has looked - in Atlantic, Mercer and Middlesex Counties. Leaf scorch has not yet been looked for across Pennsylvania, according to experts, although it has shown up in the Philadelphia area. Some oaks, for example, have been lost to scorch at the 1,050-acre Longwood Gardens in Chester County, arborist Phil Gruszka said. "We're seeing a lot of that around Philadelphia," said Paul Meyer, director of the Morris Arboretum in the Chestnut Hill neighborhood. "In the Independence Park area," he said, "a lot of trees, coming down for renovations on the mall, are apparently infested with bacterial leaf scorch." Some of his employees even found evidence of it while working on the Perlman Quadrangle at the University of Pennsylvania. In Moorestown, Clifford Pfleider, supervisor of the park and shade-tree office, wondered whether the scorch would rival Dutch elm disease, which decimated the country's elms during the first half of the 20th century. Three years ago, he said, his Burlington County town began increasing its budget for tree removal because of fears of scorch damage. Last year, it was $75,000; this year, it is $90,000. Pfleider, who discovered the disease in 1988 along Tom Brown Road near New Albany Road, said that 15 percent of the town's trees are red and pin oaks, and that the disease is now eating at a third of them. About 150 such trees planted on public land have been removed in each of the last two years, he said. Pfleider will talk about the disease at 11 a.m. today at the New Jersey Shade Tree Conferences at the Four Points Sheraton in Cherry Hill. Leaf scorch disease was discovered in the 1970s in downtown Washington by the National Park Service, and has since been found mostly in the Mid-Atlantic and Southeast-Gulf Coast areas. The bacterium that causes the disease was found in grapes in California and peach trees in the Southeast in the late 1800s, Gould said. In Southern states, Pfleider said, it has affected 28 "families of plants - grasses, herbs, shrubs, fruits and trees," including red maple, ash, elm, mulberry, peach, plum, almond and sycamore. Jim Sherald, a member of the National Park Service team that discovered the disease in Washington, said the disease "doesn't thrive much farther north" than Long Island, N.Y. He said that the disease was mostly an East Coast phenomenon, but that "there's actually a problem around Lexington, Ky." Sherald said he doubted whether the disease was on the move and speculated that it may have been around a long time - just unrecognized. But, he said, "recognition of it has certainly increased." Part of the problem is that the bacteria work slowly. "It doesn't kill the tree" right away, Sherald said, but "it gets to the point where [the tree is] so ugly you take it down." * * * Walter F. Naedele's e-mail address is wnaedele@phillynews.com # # # HemlocksHemlock Woolly Adelgid
BeechBeech Bark DiseaseSome areas of Hubbard/Perkins Conservation Area are infected. Asian Longhorned Beetle(ALB)
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V3 Last updated: November 5, 2005 Copyright © 1996-2005 New York-New Jersey Trail Conference Privacy Statement.
In NYC, the beetle has destroyed some 5,700 trees; in Illinois over
1,500 trees. In addition to infecting 108 trees in downtown Jersey
City fall 2002, it has turned up in warehouses in Secaucus, New Brunswick,
Mahwah, Linden, Cream Ridge, and Camden.