Wednesday August 26, 2009, 2:37 am
thanks terry

Wednesday August 26, 2009, 7:02 am
Thanks Terry

Wednesday August 26, 2009, 7:21 am
My first thought was NOOOOO! The black walnut when green and it's leaves are used medicinally and have been used for centuries and this cannot be replaced by anything I know of in America. They must find a cure. Thanx Terry

Wednesday August 26, 2009, 9:26 am
Hope they find a cure before it travels east. I love my black walnut trees and I would hate to lose them.

Wednesday August 26, 2009, 11:19 am
Interesting article, thanks Terry.

Wednesday August 26, 2009, 12:16 pm
Hope they find a Curr.

Wednesday August 26, 2009, 1:27 pm
Green Black Walnut is important to grow...Plant trees

Wednesday August 26, 2009, 2:19 pm
Very sad. The black walnut is packed with extra minerals over the english walnut tree. I hope they can find the cause of the problem or develop a more disease resisitant black walnut. Hope they don't go the way of the elegant elms!
Thanks Terry

Wednesday August 26, 2009, 4:57 pm
Fungal disease attacks black walnut trees in eight Western states
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By Li Lou
llou@sacbee.com
Published: Wednesday, Aug. 26, 2009 - 12:00 am | Page 1B

Diners in the courtyard of Sophia's Thai Bar and Kitchen in Davis will want to enjoy the shade while they can, because the black walnut tree providing the canopy is at risk.

"Thousand cankers disease," the coined name for a newly discovered pathogen, is infecting and slowly killing hundreds of black walnut trees in California and seven other Western states.

The disease is caused by a previously undescribed fungus hitchhiking on a tiny bark beetle native to California and widely distributed from San Diego to Shasta counties.

By itself, the walnut twig beetle does limited damage. But the aggressive fungus it carries can kill a walnut tree in several years, said Steven Seybold, a forest entomologist with the Davis-based Pacific Southwest Research Station and an affiliate of the University of California, Davis, entomology department.

"The beetle has been collected in California for a long time," said Charles Leslie, a staff research associate for the walnut improvement program in the UC Davis department of plant sciences. "But we don't know yet if the fungus is new to the trees."

Its high genetic diversity "suggests that it may have been in the U.S. for a long time, but it is behaving like an invasive pathogen," Seybold said.

The fungus was first identified in 2008 by Ned Tisserat, a plant pathologist at Colorado State University, who named the disease "thousand cankers." It also has been found in Colorado, Arizona, Idaho, New Mexico, Oregon, Utah and Washington.

Because the disease is already present throughout California, Seybold said, continued high levels of crown dieback and tree death are anticipated.

California black walnut – different from the commercial variety commonly called English walnut that is grown in the Central Valley – is known more as a shade tree than for its hard-to-crack nut. It provides food for wildlife, and its wood is used for furniture and musical instruments.

"The walnut wood is beautiful, and its golden natural color always catches eyes," said Dave Lynch, owner of Guitar Workshop in midtown Sacramento. Lynch, a guitar player and craftsman, once built several guitars of walnut for a performance.

Seybold said the disease and the beetle can affect the English walnut, as well, but those trees seem to have a lower incidence of infection in the field.

"All reports at this point indicate it does not attack English walnut," said Steve Lyle, director of public affairs for the California Department of Food and Agriculture.

Yet, scientists and commercial growers are concerned. The state's $754 million walnut industry involves more than 4,000 growers and more than 200,000 acres in the Central and coastal valleys, according to the California Walnut Commission. That accounts for 99 per cent of the U.S. commercial supply and two-thirds of the world's stock.

The primary disease symptom is dark-stained spots on the outer bark of branches, which – when peeled off – reveals dead tissue in the phloem and cambium layers of bark. Infected trees also show yellowing and thinning of the upper crown; wilting leaves; flagging branches; dieback and eventual death, sometimes all within three years.

That could be bad news at Vic's Ice Cream shop on Riverside Boulevard in Sacramento.

"Black walnut ice cream is one of our specialties," said Craig Rutledge, owner of the neighborhood ice cream parlor that has made its own ice cream from scratch since 1947. "It is something customers look forward to in winter. It is one of the oldest flavors we had and still make," Rutledge said.

Seybold said there are no tested methods for managing the disease. His lab is working on an attractant to monitor the beetle, but removing infected trees, and burning or grinding them, is probably the best practice, he said.

UC Davis researchers are participating in a federally funded project to collect infected branches and confirm the extent of the disease, according to the entomology department.

Black walnut is widely planted in Yolo County as an ornamental tree, lining roads and ranches.

The 300 to 500 black walnut trees in Davis "have a lot of heritage in town," said urban forest manager/city arborist Rob Cain. "They are a community asset."

Cain said the city would like to partner with the university to find a cure. Meanwhile, the city wants residents to report any walnut tree that isn't doing well.

Black walnut trees along Pedrick Road are showing evidence of thousand cankers disease, said Seybold.

"Davis and many other Central Valley towns are green and shaded islands within a very hot and open environment," he said. "If we lose our walnuts in Davis, the city will search for other options for shade cover and may have to select more non-native trees as a solution. This will change the character of the city. I would miss seeing these beautiful trees if they would all die."
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Wednesday August 26, 2009, 5:39 pm
Thanks for this one!!!!

Wednesday August 26, 2009, 7:34 pm
Thanks Terry.This is quite disturbing,to say the least.I do hope they find a cure,and soon.