UC Davis doctoral student Jackson Audley discusses bark beetles at a recent bark beetle open house, coordinated by Steve Seybold, at the Bohart Museum of Entomology. (Photo by Kathy Keatley Garvey)

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, wreaking havoc on native black walnut trees.

Enter doctoral student Jackson Audley of the Steve Seybold lab, UC  Department of Entomology and Nematology. He will present a seminar on "Protecting Trees from Bark Beetle Attacks Utilizing Semiochemical Repellents: A Case Study with the Walnut Twig Beetle” at a seminar from 4 to 5 p.m., today (Wednesday, Oct. 25) in Room 3001 of the Plant and Environmental Science Building.

The seminar is part of the UC Davis Forest Biology Research Center Seminar Series and his presentation is a preview of his thesis project.

"In this talk I will discuss the theoretical construct of semiochemical repellents for protecting trees from attack by bark beetles and demonstrate the process of developing a repellent tool with my work on the walnut twig beetle, Pityophthorus juglandis, the vector of thousand cankers disease in walnuts," Audley says in his abstract. "Bark beetles can constitute a significant threat to tree health and are a significant disturbance agent in forest ecosystems. Semiochemicals have been successfully utilized to protect individual to stands of susceptible trees from various bark beetle pests. Most of this work has been conducted in coniferophagous bark beetle systems. My work here at UC Davis has been focused on bringing those same techniques into studying an invasive, hardwood-attacking bark beetle system."

Audley received his bachelor's degree in wildlife biology and natural resource recreation and tourism in 2009 from the University of Georgia, and his master's degree in forestry in 2015 from the University of Tennessee. As a master's student, he did research on the walnut twig beetle, including treatment tests.

The walnut twig beetle is believed to be native to Arizona, California, New Mexico and Mexico.  In 2006, plant pathologist Ned Tisserat and entomologist Whitney Cranshaw of Colorado State University identified the pathogen in declining black walnut trees in central Colorado. The disease has now spread throughout much of the United States.

"Often the first symptoms of thousand cankers disease (TCD) are flagging and yellowing leaves and branch dieback," says Seybold, one of the pioneering TCD researchers. He is a chemical ecologist with the USDA Forest Service, Pacific Southwest Research Station, Davis, and a lecturer/researcher with the UC Davis Department of Entomology and Nematology. "Affected branches show sap staining and pinhole-sized beetle holes. Beneath the surface are dark stains caused by the fungus."

"The fungus enters the tree through the feeding or reproductive activities of the beetle, and colonizes and kills the phloem and cambium of the branches and main stem," according to the UC Integrated Statewide Integrated Pest Management Program website, content that's the work of Steve Seybold and entomologist Mary Lou Flint, then associate director of of Urban and Community IPM, and now UC Extension entomologist emerita. The disease gets its name from the large number of dark cankers that rapidly develop on affected branches.

The UC Davis Forest Biology Research Seminars, which began Oct. 11, are held Wednesdays at 4 p.m. in Room 3001 of the Plant and Environmental Science Building.

The remaining schedule includes: 

Nov. 1 – Alison Scott, postdoctoral student, UC Davis Department of Plant Sciences, “The Polyploid Origin and Evolutionary History of California Redwoods”

Nov. 15 – Brian Smithers, Ph.D student, Ecology Graduate Group, "Mechanisms of Range Shifts in Great Basin Sub‐Alpine Bristlecone Pine Forests."

Nov. 29 – Sarah Bisbing, assistant professor, Forest Ecosystem Science, Department of Natural Resources and Environmental Science,  University of Nevada, Reno, "Looking Backward to See Forward: Causes and Consequences of Altered Disturbance and Climate on Western Conifer Forests.”

Dec. 6 ‐ Ryan Tompkins, Forest Silviculturist, U.S. Forest Service/Plumas National Forest, “Sierra Nevada Silviculture in the New World Order: Challenges, Uncertainties, and Opportunities”

For more information, contact David Neale at dbneale@ucdavis.edu.

Postdoctoral scholar Bodil Cass of UC Davis

That's what postdoctoral scholar Bodil Cass of the Jay Rosenheim lab, University of California, Davis, will discuss at her seminar from 4:10 to 5 p.m., Wednesday, Oct. 25 in 122 Briggs Hall, UC Davis campus. Admission is free, and the seminar is open to all interested persons.

"Citrus is a major agricultural industry in California with a established integrated pest management (IPM) program," she says. "However, the IPM guidelines for citrus are based on years of experience and careful field research in navel oranges, and have not been updated to accommodate the recent dramatic increase in mandarin acreage in the San Joaquin Valley.  We know oranges and mandarins are very different plants, but not which practices need to be modified to effectively control pests in mandarins."

Cass says that updating the IPM guidelines for "a new citrus species is a substantial challenge, given the scale and pace of citrus production.  We are using a combination of ecoinformatics--data mining of pest management records provided by cooperating citrus growers--and field experiments to expand our understanding of the arthropod pest complex in California citrus.   Analyses of the historical commercial data indicate that fork-tailed bush katydids, Scudderia furcata, which are a key pest in oranges, very rarely damage some species of mandarin.  We are using field experiments to test hypotheses to explain this intriguing observation, and to determine whether katydids are indeed a pest at all in mandarins."

Bodil Cass in the field.

A native of the state of Queensland, Australia, Cass is an accomplished scholar who holds several degrees:

• A bachelor's degree (2005) from the University of Queensland, where she graduated with high distinction and a dean's commendation for high achievement. (She completed the Advanced Studies Program in Science in 2005, and the Enhanced Studies Program in Chemistry, 2012)
• Honors Integrative Biology (2006), University of Queensland, with high distinction and valedictorian
• Doctorate in Interdisciplinary Program in Entomology and Insect and minor in ecology and evolutionary biology (2015) from the University of Arizona (4.0 GPA)

Cass joined the lab of Jay Rosenheim, UC Davis professor of entomology, in 2016, and also serves as an associate in the Center for Population Biology at UC Davis.  She has published her work in Oecologia, Biological Journal of the Linnean Society, Microbial Ecology, Research in Microbiology, Science, and PLoS Genetics,  PLoS Biology and PLoS Pathogens, among other journals.

A member of the Entomological Society of America (ESA), Cass delivered oral presentations at the ESA annual conferences in 2011 and 2015, and also at the 2016 International Congress of Entomology (ICE), co-chaired by UC Davis chemical ecologist Walter Leal and held last September in Orlando, Fla. She is the co-principal investigator of a 2017 grant awarded by the Citrus Research Board.

Cass has also won a number of fellowships and awards, including national awards in the  P.E.O. International Peace Scholarship Program in both 2008 and 2009.

It's not at all surprising that one of the many awards she won in the beginning of her career was the "Smart Women, Smart State Award" in the undergraduate category, statewide competition (Queensland) in 2005.

You can't get any more Halloween than a bold (daring) jumping spider with orange spots!

This common North American spider was hanging out yesterday on our showy milkweed, Asclepias speciosa, trying to look like a spectator instead of a predator.

The orange spots indicate it's a juvenile Phidippus audax. As it matures, those spots will turn white.  It can jump 10 to 15 times its body length, deploying its silk "lifeline" when it's jumping for prey or evading predators, according to Wikipedia. It hunts only in the daytime.

Yesterday, resplendent in its iridescent chelicerae (mouthparts or "fangs"), the eight-eyed, eight-legged dark hairy spider crawled around the broad leaves of the milkweed, sharing its home with assorted lady beetles, aphids, wasps and an occasional butterfly (Monarchs, Gulf Fritillaries and skippers).

It soaked up some sun and then apparently decided that the telephoto camera lens represented a clear and present danger, too bold and too daring. 

Science journalist Richard Harris

So begins National Public Radio science journalist Richard Harris in his chapter, “Broken Culture," in his newly published book, Rigor Mortis: How Sloppy Science Creates Worthless Cures, Crushes Hope and Wastes Billions.

Darwin was driven by curiosity; he didn't start out with a “coherent hypothesis,” Harris says. Plus, Darwin "had no need to hustle for money,” and "he was in no hurry to publish his discoveries.”

Today the “high pressure of competition can tempt even the best scientists into dangerous territory,” Harris warns in his 278-page book.

You can hear what Harris says about sloppy science/faulty research when he travels from his home in Washington, D.C. to the University of California, Davis, campus to deliver a Storer Lecture.

Harris will speak on “Common Errors that Bedevil Biomedical Research and How to Fix Them,” from 4:10 to 5 p.m., on Wednesday, Oct. 25 in the UC Davis Student Community Center. The event is free and open to the public. A book signing will follow the lecture.

The lectureship, established in 1960, is funded through a gift from Professor Tracy I. Storer and Dr. Ruth Risdon Storer to bring eminent biologists to the UC Davis campus. Speakers have included Nobel laureates, members of the National Academy of Science and acclaimed authors in the life sciences and medicine.

“Richard Harris has written a very important and unsettling book based on his careful investigation of the biomedical research enterprise,” said Mark Winey, distinguished professor of Molecular and Cellular Biology and dean of the College of Biological Sciences, UC Davis, who is hosting the journalist. “We can expect an intriguing and thought provoking lecture.”

In his book, Harris relates that American taxpayers spend $30 billion annually funding biomedical research. “We all rely on biomedical research for new treatments and cures,” Harris points out. “But this critical enterprise is not in the best of health itself.  Most experimental treatments fail. One reason is that the underlying research does not hold up to scrutiny. Scientists find that far too often that they are unable to repeat experiments that other researchers have carried out.”

By some estimates, half of the results from these studies can't be replicated elsewhere—the science is simply wrong, Harris asserts.

The national award-winning science journalist, who grew up in the San Francisco Bay Area, has covered science, medicine and the environment for NPR Radio since 1986. A graduate of UC Santa Cruz with a bachelor's degree in biology, he began his journalism career as a reporter for the Livermore (Calif.) Tri-Valley Herald. He later joined the San Francisco Examiner as a science writer. He is a past president of the National Association of Science Writers and the Northern California Science Writers' Association.

We just finished reading Rigor Mortis today. It's not only an eye opener, but a call to action. It's as easy to read as a well-documented and detailed newspaper investigative piece, complete with patient and researcher interviews and anecdotes. It zeroes in on “the constant scramble for research dollars” and the fact that scientists' “promotions and tenure depend on their making splashy discoveries.”  Sadly, it's often quantity over quality in the "publish-or-perish" world of academia.

Harris writes about egregious research, targeting cancer, heart disease, Lou Gehrig's disease, diabetes, and other diseases--diseases that can and do affect us all, either through taxpayer funding or personal/family/friend experiences.

Charles Darwin was in no hurry to publish his discoveries. Neither should today's researchers. We can and must do better.

(Editor's Note: The presentation will be recorded for later viewing. Joanna Chiu, associate professor and vice chair, UC Davis Department of Entomology and Nematology, is coordinating the Storer Lectureships in Life Sciences for the academic year. She may be reached at jcchiu@ucdavis.edu)