- Author: Akif Eskalen
The Polyphagous Shot Hole Borer (PSHB), Euwallacea sp. #1, is an invasive beetle that carries three fungi: Fusarium euwallaceae, Graphium sp. , and Acremonium sp. The adult female tunnels galleries into a wide variety of host trees, where it lays its eggs and grows the fungi. The fungi cause the Fusarium Dieback (FD) disease, which interrupts the transport of water and nutrients in over 35 tree species that are suitable for beetle reproduction.
Once the beetle/fungal complex has killed the host tree, pregnant females fly in search of a new host.
A separate invasion was recently detected in commercial avocado groves and landscape trees in San Diego county. It has been determined that the damage has been caused by another closely related species of PSHB (Euwallacea sp. #2), carrying a new species of Fusarium and Graphium. The beetle in LA, Orange, Riverside, and San Bernardino Counties are morphologically indistinguishable, but genetically distinct from the beetle found in San Diego County.
Signs and Symptoms
Attack symptoms, a host tree's visible response to stress, vary among host species. Staining, sugary exudate (B), gumming, and/or frass may be noticeable before the tiny beetles (females are typically 1.8-2.5 mm long). Beneath or near these symptoms, you may also see the beetle's entry/exit holes, which are ~0.85 mm in diameter. The abdomen of the female beetle can sometimes be seen sticking out of the hole.
Sugary exudate on trunks or branches may indicate a PSHB attack (photos A-E). Note that exudate may be washed off after rain events and therefore may not always be present on a
heavily infested branch.
PSHB attacks hundreds of tree species, but it can only successfully lay its eggs and/or grow the fungi in certain hosts. These include: Avocado, Box elder, California sycamore, Coast live oak, White alder, Japanese maple, and Red willow. Visit eskalenlab.ucr.edu for the full list.
Fusarium dieback pathogens cause brown to black discoloration in infected wood. Scraping away bark over the entry/exit hole reveals dark staining around the gallery, and cross sections of cut branches show the extent of infection. Advanced infections eventually lead to branch dieback and death of the tree
How to report a suspect tree
Please report suspected tree infestations to UC Riverside (email@example.com).
Submit the following information:
•Contact information (name, city, phone number, email)
•Suspect tree species
•Description of suspect tree's location (and/or GPS coordinates)
•Description of suspect tree's symptoms
•Photos of suspect tree and close-up photos of symptoms (see examples)
Take photos of suspect trees from several distances. Include photos of:
1. the trunk or symptomatic branches;
2. the symptoms (close-up); and
3. the entry/exit hole, if visible, with a ballpoint pen for scale (remove exudate if necessary). If dieback is observed, take a picture of the entire tree.
- Author: Cheryl Reynolds
New Pesticide Resistance Online Course with Continuing Education Units
Author: Cheryl Reynolds, UC Statewide IPM Program
An online course highlighting how pesticide resistance develops among pests is now available on the UC IPM Web site. Created primarily for pest control advisors and other licensed pesticide applicators, this course describes the mechanisms of resistance in pathogens, insects, and weeds and discusses ways to manage resistance within the different disciplines.
The online course is divided into three narrated presentations followed by a final test for each section. This course has been approved for 2 continuing education units in the “Other” category from the Department of Pesticide Regulation.
This course is based on a series of workshops held in Davis, Fresno, and at the Kearney Agricultural Research and Extension Center during the spring of 2014 presented by Dr. Doug Gubler (Dept. of Plant Pathology, UC Davis.), Dr. Larry Godfrey (Dept. of Entomology and Nematology, UC Davis), Dr. Beth Grafton-Cardwell (Lindcove Research and Extension Center and UC Riverside), and Dr. Kassim All-Khatib (UC Statewide IPM Program).
Check out the new course at http://www.ipm.ucanr.edu/training/pesticide_resistance.html.
- Author: Ben Faber
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The government of Ecuador has requested the U.S. allow avocado to be imported into the continental United States. APHIS has drafted a pathway-initiated risk assessment for this request. The draft document is available for 30 days for stakeholders to review and provide comments.
The document and instructions for submitting comments may be accessed through the APHIS Plant Import Information Web page, or this link:
- Author: Sonia Rios
Rios completed an M.S. in Plant Science with an emphasis in Weed Science from California State University, Fresno, a B.S. in Plant Science from California State Polytechnic University, Pomona
Prior to accepting her advisor position, Rios served as a staff research associate in UCCE Tulare County where she assisted advisors in all phases of applied agricultural research (field and greenhouse research on cereal crops, cotton and weed management). She was involved in approximately 30 – 40 research projects that included research testing in herbicide resistance, variety evaluations, and pest management including evaluating new herbicides and insecticides. Rios has conducted and reported agronomy research experiments through data collection that is statistically analyzed, translated and disseminated to clientele; maintained research plots; prepared educational materials for research reports and University publications that would benefit California growers, industry clientele; assisted regulatory agencies with science-based information; conducted radio interviews; and she was a regular speaker at the Tulare County Pesticide Safety meetings. In addition to working with UC, she was also her main professors' student research assistant that would help with trials on campus, assist undergraduates with their research projects and spent time in the classroom teaching.
Rios had also worked with the United States Department of Food and Agriculture (CDFA) inspecting airplanes for Japanese beetle as an Agriculture Aide I. She also worked with the United States Department of Food and Agriculture (USDA) Forest Service as a Forestry Technician.
Rios will be working in education and applied research program in tree crops production and marketing in Riverside and San Diego Counties. Primary target crops are citrus, avocados and dates, but also include other subtropical and deciduous fruit and nut crops, such as pomegranates, figs, mangos and walnuts.
She will facilitate interactions and information exchange among campus based academic, Cooperative Extension advisors and community stakeholders. Focus is expected on increasing productivity and efficiency of commercial tree crops operations, thus maximizing the return on invested capital, and at the same time, providing consumers with a high quality, safe and reasonably-priced product. The advisor will address emerging production issues in subtropical fruit crops including: horticulture, entomology, plant pathology, integrated pest management, plant nutrition and variety testing. She will be working closely with the subtropical horticulture industries, local growers and members of the subtropical horticulture and nuts and fruits workgroup to identify research areas of highest priority. Her contact information is as follows:
Cooperative Extension Riverside County 21150 Box Springs Road, Suite 202 Moreno Valley, CA 92557-8718
Email Address: firstname.lastname@example.org
- Author: Ben Faber
John Letey, Jr.
University of California–Riverside (UCR) Distinguished Professor of Soil Physics and Soil Physicist Emeritus John Letey, Jr. passed away on 14 September. He was 81 years old.
He received his B.S. degree at Colorado State University and Ph.D. degree at the University of Illinois. He joined the faculty in the Department of Irrigation and Soil Science at UCLA in 1959, but with the phasing out of agriculture at UCLA, he elected to join the Department of Soil Science at UCR in 1961 and enjoyed a distinguished career in research, teaching, administration, and service at the university. During his tenure, Dr. Letey served as chair of the Department of Soil and Environmental Science from 1975 to 1980, director of the Kearney Foundation of Soil Science from 1980 to 1985, and director of the University of California Center for Water Resources from 1999 to 2003. He was instrumental in the establishment of the Environmental Sciences undergraduate major at UCR, which was one of the first of its kind in the United States. He recognized and appreciated the critical link between science and policy and built teams and research to address it.
Letey's research focused on all aspects of water quantity and quality related to irrigated agriculture that provided both applied and basic information critical to establishing sound water resource management. Topics of research included irrigation, drainage, salinity, pesticide transport, plant–water relations, nitrogen, soil aeration, and polymers. He was also recognized as one of the world authorities on water-repellent soils and the utilization of surfactants. He wrote a biography of his education and professional career that can be accessed on the following website: http://envisci.ucr.edu/downloads/johnleteycareer.pdf.
Letey was a fellow of SSSA, ASA, and AAAS and was awarded the SSSA Soil Science Distinguished Service Award in 2005 and the SSSA Soil Science Research Award in 1970. He authored or co-authored more than 300 technical publications concerning chemical, water, and gas movement through soil before retiring from UCR in 2002. In 2007, he published a fictional book titled, The Folly of Fearing Death (PublishAmerica, Baltimore).
In 2003, Letey and Ardyth Stolzy, wife of the late Professor of Soil Physics Emeritus Lewis H. Stolzy, combined the Letey Soil Environmental Fund and the Lewis Stolzy Memorial Fund into the Stolzy–Letey Endowment in Soil and Environmental Science. The Stolzy–Letey Fund is now used for the benefit and support of the students in the Department of Environmental Sciences at UCR.
Letey was a friend and mentor to students, visiting scholars, and faculty across the world. He served his research community, church, and family with great love and personal integrity. He is survived by his wife, Sonia; three children, Laura Petersen, Don Letey, and Lisa Smith; 10 grandchildren; and 11 great-grandchildren./h3>