Backyard Orchard News
The killer: thousand cankers disease. The victim: native black walnuts. The speaker: Steve Seybold.
Seybold (right), a research entomologist with the Chemical Ecology of Forest Insects, USDA Forest Service, Pacific Southwest Research Station, Davis, will speak on “Walnut Twig Beetle and Thousand Cankers Disease: Characterizing an Emergent Threat to Forest and Agroecosystems in North America” at a noonhour seminar sponsored by the UC Davis Department of Entomology. It will take place from 12:10 to 1 p.m., Wednesday, May 19 in 122 Briggs Hall on Kleiber Drive.
Thousand cankers disease is a newly discovered disease that is becoming a “significant problem” in California and seven other western states and could very well spread throughout the United States, researchers say.
“Thousand cankers disease, caused by a newly described fungus spread by the tiny walnut beetle, has been detected in 15 California counties from Sutter County to Los Angeles,” said Seybold, a chemical ecologist and affiliate of the UC Davis Department of Entomology.
How can a tiny little beetle fell a mighty tree? When it's associated with a specific fungus, a newly described fungus that's so new it has no name.When it tunnels into the wood, the walnut twig beetle (Pityophthorus juglandis) carries the fungus (proposed name of Geosmithia morbida) with it. Often the first symptoms of the disease are flagging and yellowing leaves and branch dieback. Affected branches show sap staining and pinhole-sized beetle holes. Peel back the bark and you'll see dark stains caused by the fungus.
To date, the disease has been found in Utah, Colorado, New Mexico, Arizona, Idaho, Washington as well as California.
“The potential spread of the disease to the eastern United States is now of great concern, especially through movement of infested/infected raw wood and firewood,” Seybold said.
The walnut twig beetle, believed to be native to Arizona, California, New Mexico, and Mexico, was first collected in Los Angeles County more than 50 years ago.
The disease was first noticed in canker-riddled black walnuts in Utah and Oregon in the early 1990s, but scientists attributed that to environmental stress. In 2006, plant pathologist Ned Tisserat and entomologist Whitney Cranshaw of Colorado State University identified the pathogen and characterized its association with the beetle in declining black walnut trees in central Colorado.
This is a very serious disease of black walnuts. Let's hope they don't go the way of the American chestnut or the American elm.
Walnut Twig Beetle
If you have a bee hive, you most likely have mites.
Varroa mites, those blood-sucking parasites that latch onto the brood and also thrive on the adult bees, can weaken and destroy a hive.
Extension apiculturist Eric Mussen, member of the UC Davis Department of Entomology faculty, frequently fields calls about varroa mites.
In his latest edition of from the UC apiaries, he points out that "obtaining fumigants for varroa mite control may be somewhat difficult at this time for beekeepers."
"I haven't checked on the Apiguard® situation recently, but shipments from Europe had been held up, apparently by U.S. customs," Mussen wrote. "The other desired fumigant, Mite Away II pads, are vanishing from the market quickly. They are out of production and soon will not be available. The reason behind this is because NOD Apiary Products, in Canada, has decided to stop producing the pads and instead offer a formic acid product in strip form."
Today we spotted a varroa mite on a foraging bee. The bee, a golden Italian, was nectaring lavender.
Unfortunately, a nasty little parasite was eating at her.
Our catmint is in mint condition.
So is the cat.
The catmint (Nepeta mussinii) is a member of the mint family (Lamiaceae or Labiatae). It's a perennial with two-lipped blue or blue-violet flowers that blooms from spring through fall. It grows so well that it can become invasive.
Just like the cat.
As soon as the temperature hits 50 degrees, the honey bees are all over it, poking their heads inside the floral caps as if trying on hats.
And the cat, Xena the Warrior Princess, is right there. She likes to sniff, nibble and rub the catmint.
If she were in a catnip (Nepeta cataria) patch--catnip has whitish-pinkish flowers--she would be rolling in it in a crazy euphoric frenzy.
Although feline reactions differ considerably, the two plants belong to the same mint family.
Plant catnip and cats will roll wildly in it. Plant catmint and it's sniff, nibble and rub.
Bee on Catmint
Like an Acrobat
Cat Sniffing Catmint
It wasn't an itsy bitsy spider.
And it didn't climb up the water spout.
It was climbing all over the tower of jewels, ready to stalk and pounce on prey.
We spotted this male jumping spider in the genus Phidippus (as identified by Lynn Kimsey, director of the Bohart Museum of Entomology at UC Davis) cruising the interstate of a nine-foot-high tower of jewels (Echium wildpretii).
The tower of jewels is a bee-friendly plant, but it's also spider-friendly.
The eight-eyed jumping spider (four large eyes on its face and four smaller eyes on top of the head) is considered an excellent predator because of its keen eyesight and amazing speed. Although it's only about two centimeters (less than 0.8) long, it can jump about 40 to 50 times its length. It's distinguished, too, by its iridescent green chelicerae or mouthparts.
The kneeling photographer and the jumping spider went eye to eye--well, two eyes versus eight eyes--and then the spider crawled under a stem.
I was hoping it would jump.
Ant specialist Andrea Lucky, who will receive her doctorate in entomology on June 10 from UC Davis, will speak on the evolutionary history of ants on Wednesday, May 12 in 122 Briggs, UC Davis.
This is her "exit seminar" but it's doubling as part of the spring seminar series. Her talk, from 12:10 to 1 p.m., will be Webcast live. To tune in, access this site.
She researches the evolutionary history of ants in the geological complex region of Australasia, Melanesia and the islands of the Western Pacific.
“I use a combination of traditional morphological taxonomy and molecular phylogenetics to interpret how, when and where individual lineages diversified within this complex landscape,” said Lucky, who maintains a research website and studies with major professor Phil Ward. “In addition to my work on the biogeography of ants, I am also involved in biodiversity assessment and conservation using ants in Papua, New Guinea.”
You can watch a mini- interview of her in New Guinea on YouTube.
Lucky completed her undergraduate degree at Brown University in Providence, RI, where she majored in biology with an emphasis on ecology and evolutionary biology.
After receiving her bachelor’s degree, she traveled to Ecuador as a Fulbright Fellow, where she worked with insects in the Amazon.
Lucky entered the doctorate program in the UC Davis Department of Entomology in 2004 and completed her degree in the lab of Phil Ward.
After receiving her Ph.D., she will move on to a postdoctoral scholarship at North Carolina State University, Raleigh, where she will work with Rob Dunn on a project examining geographic variation in ants and the processes they mediate.
If you miss any of the UC Davis Department of Entomology webcasts, they're archived.
These webcasts are a good resource for entomologists, would-be entomologists, and folks of the curious-sort who just want to learn more about the exciting world of science.
And, somewhere out there, there's another young entomologist who will follow in Andrea Lucky's footsteps...trailing ants.
Andrea Lucky in New Guinea