- Author: Kathy Keatley Garvey
That quote sound familiar? Chemical ecologist Jacques Le Magnen (1916-2002) said that back in 1970.
World-renowned organic chemist Wittko Francke (right) of the University of Hamburg, Germany, called attention to Le Magnen's quote at a UC Davis Department of Entomology seminar on Wednesday noon, Dec. 8.
It bears repeating: "Nature is more a world of scents than a source of noise."
Insects communicate in a chemical language or chemical signals, Francke told the crowd.
Indeed, scientists have long known that methods that can attract or repel insects have important applications for agricultural pests and medical entomology.
Francke told how a queen bee secretes compounds that regulate development and behavior of the colony, and how an orchid releases the scent of a female wasp to attract male wasps— a scent that results in pollination. He also touched on the “calling cards” of a number of other insects, including bumble bees, wasps, pea gall midges, stingless bees, bark beetles and leafminers. He pointed out that that plants, too, send chemical signals.
UC Davis graduate students James Harwood and Amy Morice of the James R. Carey lab video-taped the seminar. It will be online soon at http://entomology.ucdavis.edu/news/webcastlinks.html
Francke was introduced by chemical ecologist-forest entomologist (and UC Davis Department of Entomology affiliate) Steve Seybold of the USDA Forest Service, Pacific Southwest Research Station, Davis.
No stranger to UC Davis, Francke previously collaborated with chemical ecologist Walter Leal, professor and former chair of the UC Davis Department of Entomology, on attractants for navel orangeworm.
In his talk, Francke mentioned Leal’s discovery of a sophisticated mechanism for the isolation of the chemical communication channels of two species of scarab beetles.
Seybold and Francke are collaborating on the chemical signals of the walnut twig beetle, which in association with a newly described fungus, causes thousand cankers disease, a killer of walnut trees.
Thousand cankers disease (TCD) is now found in seven western states, plus Tennessee. Seybold is a key researcher in California.
Scientists believe that TCD occurs only on walnut, predominantly native black walnut, Juglans californica and J. hindsii, although the disease has been recorded on 10 species of walnuts or their hybrids in California.
Often the first symptoms of TCD are flagging and yellowing leaves and branch dieback, said Seybold, who has been studying the chemical ecology and behavior of bark beetles for more than 25 years. Affected branches show sap staining and pinhole-sized beetle holes. Beneath the surface are dark stains caused by the fungus.
A USDA/UC Davis research team is tracking the pathogen and the beetle throughout California, particularly in commercial orchards.
That all points back to “Nature is more a world of scents than a source of noise.”
- Author: Kathy Keatley Garvey
Remember the exciting news article published in November of 2009 in Science Daily about how an orchid species on the Chinese island of Hainan "fools its hornet pollinator by issuing a chemical that honey bees use to send an alarm?"
The research was first published in Current Biology, a Cell Press publication.
"The discovery explains why the hornets, which capture honey bees to serve as food for their larvae, have been observed to literally pounce on the rewardless Dendrobium sinense flowers," the Science Daily author wrote.
Can you imagine? Hornets "detect" one of their favorite foods--honey bees--and they pounce on the flower and come up empty-handed or "empty-mouthed?"
The orchids produce a deceptive chemical, a compound called Z-11-eicosen-1-ol, described as "a rarity even in the insect world."
One of the researchers involved in this study--and hundreds of other insect communication studies--is world-renowned chemical ecologist Wittko Francke (top photo) of the University of Hamburg, Germany.
And now he's coming to the University of California, Davis, to present a seminar.
Francke will speak on "Insect Semiochemicals: Structural Principles and Evolution" at a UC Davis Department of Entomology seminar on Wednesday, Dec. 8 from 12:10 to 1 p.m. in 122 Briggs Hall, off Kleiber Hall Drive. He'll be introduced by host and fellow chemical ecologist Steve Seybold of the USDA Forest Service, Pacific Southwest Research Station, Davis, and an affiliate of the UC Davis Department of Entomology.
"Nearly everyone in the field has collaborated with him at some level; he has been a consummate mentor to younger chemical ecologists and has always been generous with his time, intellect, and chemical skills to everyone in that community," Seybold said. "He is remarkably brilliant in that he sees patterns in the make-up and synthesis of bio-organic compounds that most biologists, and even many chemists, may overlook."
Francke’s talk, open to the public, will be webcast live and then archived on the Department of Entomology's website. This is the last in the series of the department’s fall seminars.
- Author: Kathy Keatley Garvey
And also barbecued marinated ball tip and chicken quarters with barbecued beans and salad.
You can't ask for anything better than that! Bugs on the agenda and ball tip on the plates! (Well, salad, too!)
The occasion: the last Nor Cal meeting of the year. The members and their guests will meet from 9:15 a.m. to 2:30 in the Contra Costa Mosquito and Vector Control District, 155 Mason Circle, Concord.
One of the hot topics is a newly discovered disease that kills black walnut trees.
Research entomologist Steve Seybold (above) of the Pacific Southwest Research Station, USDA Forest Service, Davis, and an affiliate of the Department of Entomology, University of California, Davis, will provide an update on the disease at 10:15 a.m. Caused by a newly described fungus (Geosmithia morbida) spread by the tiny walnut twig beetle (Pityophthorus juglandis), it is known as "thousand cankers disease."
The disease is becoming a "significant problem" in California and seven other western states and could very well spread throughout the United States. It was detected in Tennessee last summer.
The society's agenda:
9:15 a.m.
Registration for club members and guests, with coffee
9:30 a.m.
“Bedding Plant/Container Color Alliance in California,” Christine Casey, UC Davis
10:15 a.m.
“Thousand Cankers Disease” by Steve Seybold of the USDA Forest Service and an affiliate of the UC Davis Department of Entomology
11 a.m.
“Statewide Invasive Insect and Mite Activities, 2009-2010, by Kevin Hoffman, Pest Detection and Emergency Projects, California Department of Food and Agriculture
11:45 a.m.
Annual business meeting; election of officers
12 Noon
Catered lunch by Kinder’s Custom Meats (barbecued marinated ball tip and chicken quarters with barbecued beans, tossed green salad, potato and fresh fruit salads, assorted soft drinks and cookie for $15)
1:15 p.m.
“UC Berkeley Drywood Termite Inspection Research Update” by Robin Tabuchi of UC Berkeley
2 p.m.
“Oriental Fruit Moth Parasitoid" by UC Integrated Pest Management (UC IPM) Program Advisor Walter Bentley, UC Kearney Agricultural Center, Pariier
The Northern California Entomology Society meets three times a year: the first Thursday in February in Sacramento; the first Thursday in May, at UC Davis; and the first Thursday in November in Concord. Membership is open to the public; dues are $10 year. The president is agricultural biologist Matthew Slattengren of the Contra Costa County Department of Agriculture.
Extension apiculturist Eric Mussen of the UC Davis Department of Entomology faculty serves as the secretary-treasurer and is taking reservations for the luncheon. He may be reached at ecmussen@ucdavis.edu or call (530) 752-0472.
The society is comprised of university faculty, researchers, pest abatement professionals, students and other interested persons.
The officers are hoping to build up membership in the organization, so if you have a keen interest in bugs--or what's bugging California--sign up!
- Author: Kathy Keatley Garvey
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 in Knox County in east Tennessee. This marks the first detection of the disease east of the Mississippi River.
Previously, the disease was known to eight western states: Arizona, California, New Mexico, Colorado, Idaho, Oregon, Utah and Washington.
And now, Tennessee. It's probably in other states across the Great Plains and east of the Mississippi River, as well.
The disease, caused by the walnut twig beetle (Pityophthorus juglandis) in association with a newly described fungus with the proposed name of Geosmithia morbida), occurs only on walnut species. Eastern black walnut is one of the most susceptible species.
By itself, the walnut twig beetle doesn't present a major problem. Together they wreak havoc.
A pest alert, distributed by the U.S. Forest Service and co-authored by Davis-based researcher Steve Seybold, is sounding the alarm
Seybold, research entomologist with the U.S. Forest Service, Pacific Southwest Research Station, Davis, and a faculty affiliate of the UC Davis Department of Entomology, says the disease symptoms to watch for are branch mortality; numerous small cankers on branches and the main stem of the tree; and the entry and exit holes of the tiny bark beetles. (See news article on presence of the disease in Davis.)
In an attempt to stop the spreading of the disease, the Tennessee Department of Agriculture (TDA) plans to quarantine Knox County to prohibit the movement of firewood and black walnut nursery stock and to limit the movement of black walnut timberland.
The TDA's Division of Forestry estimates that the state has 26 million black walnut trees (both on public and private land). They are valued as high as $1.47 billion.
That's "billion" with a "B."
The losses would be more than monetary, though.
We received a telephone call from a Washington state resident today who is worried--and rightfully so--that his two 100-year-old majestic black walnut trees might contract the disease.
And to think that they could be felled by this duo: a fungus hitching a ride on a tiny walnut twig beetle boring into a tree.
It's a beetle that's smaller than a grain of rice.
- Author: Kathy Keatley Garvey
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.
You can listen live to the webcast. The lecture later will be archived on the department's website.
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.
