Trinity County Cooperative Extension
University of California
Trinity County Cooperative Extension

Posts Tagged: Pityophthorus juglandis

A Sign of the Times: Why This Black Walnut Tree Is Dying

Forest entomologists Steve Seybold (right) and Jackson Audley stand by a 150-year-old black walnut tree on the 100 block of E Street. It is dying of thousand cankers disease. (Photo by Kathy Keatley Garvey)

If you've ever walked into the courtyard on the 100 block of E Street in downtown Davis, Calif., you've probably noticed the massive black walnut tree near Sophia's Thai Bar and Kitchen. It's about 150 years old, 50 feet in height, and measures about...

Forest entomologists Steve Seybold (right) and Jackson Audley stand by a 150-year-old black walnut tree on the 100 block of E Street. It is dying of thousand cankers disease. (Photo by Kathy Keatley Garvey)
Forest entomologists Steve Seybold (right) and Jackson Audley stand by a 150-year-old black walnut tree on the 100 block of E Street. It is dying of thousand cankers disease. (Photo by Kathy Keatley Garvey)

Forest entomologists Steve Seybold (right) and Jackson Audley stand by a 150-year-old black walnut tree on the 100 block of E Street. It is dying of thousand cankers disease. (Photo by Kathy Keatley Garvey)

Walnut twig beetles tunnel into branches and trunks of walnut (Juglans) where they create galleries for mating and reproduction. In association with a canker producing fungus, Tthey cause a disease known as thousand cankers disease. This tree is in downtown Davis, Calif. (Photo by Kathy Keatley Garvey)
Walnut twig beetles tunnel into branches and trunks of walnut (Juglans) where they create galleries for mating and reproduction. In association with a canker producing fungus, Tthey cause a disease known as thousand cankers disease. This tree is in downtown Davis, Calif. (Photo by Kathy Keatley Garvey)

Walnut twig beetles tunnel into branches and trunks of walnut (Juglans) where they create galleries for mating and reproduction. In association with a canker producing fungus, Tthey cause a disease known as thousand cankers disease. This tree is in downtown Davis, Calif. (Photo by Kathy Keatley Garvey)

This massive, 150-year-old black walnut tree on the 100 block of E Street, Davis, is dying of thousand cankers disease. (Photo by Kathy Keatley Garvey)
This massive, 150-year-old black walnut tree on the 100 block of E Street, Davis, is dying of thousand cankers disease. (Photo by Kathy Keatley Garvey)

This massive, 150-year-old black walnut tree on the 100 block of E Street, Davis, is dying of thousand cankers disease. (Photo by Kathy Keatley Garvey)

Jackson Audley: A Case Study with the Walnut Twig Beetle

The walnut twig beetle is about the size of a grain of rice. (Photo by Kathy Keatley Garvey)

So tiny and so destructive. It's about the size of a grain of rice but it's a killer. That's the walnut twig beetle, Pityophthorus juglandis, which in association with a newly described fungus, Geosmithia morbida, causes thousand cankers disease,...

The walnut twig beetle is about the size of a grain of rice. (Photo by Kathy Keatley Garvey)
The walnut twig beetle is about the size of a grain of rice. (Photo by Kathy Keatley Garvey)

The walnut twig beetle is about the size of a grain of rice. (Photo by Kathy Keatley Garvey)

The Scholar and the Walnut Twig Beetle

Kristina Tatiossian and the ceramic mosaic of a walnut twig beetle. (Photo by Kathy Keatley Garvey)

Most people have never seen the walnut twig beetle, a tiny insect that spreads a fungal pathogen that kills walnut trees.  No wonder. The insect, measuring about 1.5 millimeters long, is much smaller than a grain of rice.  Now, however, they...

Kristina Tatiossian and the ceramic mosaic of a walnut twig beetle. (Photo by Kathy Keatley Garvey)
Kristina Tatiossian and the ceramic mosaic of a walnut twig beetle. (Photo by Kathy Keatley Garvey)

Kristina Tatiossian and the ceramic mosaic of a walnut twig beetle. (Photo by Kathy Keatley Garvey)

The poster that Kristina Tatiossian created. (Photo by Kathy Keatley Garvey)
The poster that Kristina Tatiossian created. (Photo by Kathy Keatley Garvey)

The poster that Kristina Tatiossian created. (Photo by Kathy Keatley Garvey)

A Thousand Questions about TCD

Dying Walnut Trees in Davis

Researchers have a thousand questions about thousand cankers disease (TCD), the newly discovered disease that kills black walnut trees.Chemical ecologist and forest entomologist of Steve Seybold of theĀ USDA Forest Service, Pacific Southwest Research...

Dying Walnut Trees in Davis
Dying Walnut Trees in Davis

THESE DYING WALNUT TREES in Davis, Calif., are victims of thousand cankers disease. (Photo by Steve Seybold)

Walnut Twig Beetle
Walnut Twig Beetle

ELECTRON SCANNING MICROSCOPE image of walnut twig beetle, by Andrew Graves, formerly of UC Davis.

Posted on Wednesday, December 22, 2010 at 5:51 PM

Bad News for Black Walnut Trees

Walnut Twig Beetle

The news is startling, but not totally unexpected.Thousand cankers disease, which infects and kills black walnut trees, has spread from the western United States to the eastern United States.Officials announced Aug. 5 that the disease has been detected...

Walnut Twig Beetle
Walnut Twig Beetle

TINY walnut twig beetle is cause for concern when a newly described fungus (with the proposed name of Geosmithia morbida), hitches a ride on its back when it bores into black walnut trees. Together they wreak a havoc known as "thousand cankers disease." (Photo by Kathy Keatley Garvey)

Posted on Monday, August 9, 2010 at 8:41 PM
 
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