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Western Plant Diagnostic Network News

Western Plant Diagnostic Network

First Detector News

A Quarterly Pest Update for WPDN First Detectors

Summer 2012 edition, volume 5, number 2

In this Issue

Page 1: Editor’s Note:

Pages 2 - 5: Laurel Wilt Update

Pages 6 - 7: Polyphagous Shot Hole Borer Vectors Fusarium Disease in CA Pages 7-8: New Pale Cyst Nematode on Potatoes in ID Pages 9-10: WPDN Awardees

Page 10: New UC IPM Manual

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Contact us at the WPDN Regional Center at UC Davis: Phone: 530 754 2255 Email: rwhoenisch@ucdavis.edu Web: https://wpdn.org Editor: Richard W. Hoenisch @Copyright Regents of the University of California All Rights Reserved

Dear First Detectors, Three very small invasive beetles of the subfamily Scolytinae (bark and ambrosia beetles) are wreaking havoc on trees from the east to west coast of the United States. In addition to damaging tree tissue by boring into the phloem (bark beetles) and xylem (ambrosia beetles), all three beetles featured in this newsletter vector fungal pathogens that can eventually kill the host. Please see the USDA Forest Service presentation Exotic Bark and Ambrosia Beetles in the US. In this edition we update the status of the redbay ambrosia beetle (RAB), Xyleborus glabratus. RAB has spread from woodlands in the southeastern U.S. into commercial avocado orchards in Florida. Please see the Summer 2010 and Spring 2011 WPDN news regarding the RAB and other beetles. Also in this edition we highlight an emerging pest in southern California, an ambrosia beetle called the polyphagous shothole borer (PSHB) in the genus Euwallacea. This beetle vectors a Fusarium fungus into various tree species. Both insect and pathogen have yet to be identified to species. We introduced a debilitating disease of walnut called Thousand Cankers Disease (TCD) in the Winter 2010 WPDN news, and the status of this problem will be updated in Fall 2012. The walnut twig beetle, Pityophthorus juglandis, vectors a fungus, Geosmithia morbida, which is lethal for many species of black walnut and is finding its way into commercial English walnuts. This beetle and fungus cause branch dieback and eventual collapse of the crown of afflicted trees.

Finally there is some good news for the WPDN. We now have 4,700 First Detectors in our western region, and several members of the WPDN team have received awards. And as always, you may view the WPDN and the NPDN family of newsletters and archives at:

Newsletters

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Western Plant Diagnostic Network News

Laurel Wilt in the Southeast US and its consequences for the West

In 2002, as part of the USDA Forest Service Early Detection & Rapid Response Pilot Project, three specimens of the redbay ambrosia beetle (RAB), Xyleborus glabratus Eichhoff, were captured in detection traps near Port Wentworth, Georgia. This was the first record of this Asian species in North America. Later in 2002, in coordination with APHIS (USDA Animal and Plant Health Inspection Service), additional traps were placed in the Port Wentworth area to delimit a possible establishment, but no further catches of this beetle were made. Due to the small number of beetles collected and the location of the traps near warehouses, it was thought likely that the beetles had come directly from solid-wood packing materials and had not become established in native vegetation. After initial inoculation experiments, the combination of the fungus and beetle was suspected to be the primary cause of redbay mortality. In 2004, the Georgia Forestry Commission (GFC) was also receiving reports of Redbay and Sassafras mortality in coastal areas. A multi-disciplinary team from the USDA Forest Service, SCFC, GFC, Florida Division of Forestry, and other agencies and organizations began to cooperatively evaluate the problem and its causes. In early 2005, the wilt fungus was tentatively identified as a species of Ophiostoma, and was further identified as an unknown Raffaelea species (Raffaelea is an asexual genus of ambrosia beetle symbionts related to Ophiostoma species) and later described as R. lauricola. It is quite interesting to note that Ophiostoma ulmi is the causal agent of Dutch elm disease . Growth chamber inoculations by USDA Forest Service researchers showed the fungus to be a highly virulent wilting agent in several Persea species (including avocado) and other members of the Lauraceae family. The fungus was isolated from the redbay ambrosia beetles, suggesting that the beetle was a vector of the fungus. Ambrosia beetles were found in all dying redbay trees. Fungus was found to be present in all beetles and diseased trees were found to have the fungus Ophiostoma sp, which was the cause of mortality. There are over 60 species of ambrosia beetles in the United States. of these 20 species are non-native and eight of the non-native species do not cause any economic or eco-logical harm. Ambrosia beetles are usually attracted to dying trees, however, it is evident that the red bay ambrosia beetle attacks healthy trees. On May 1, 2012, the Florida Department of Agriculture announced that laurel wilt was found in a commercial avocado grove in Miami-Dade County, where there are 6,773 production acres of avocado.

The rate of spread of the beetle is estimated at about 20 miles per year (without help from humans, who may inadvertently transport it in firewood or infested plants). 2009 saw the expansion of laurel wilt into south Florida and coastal Mississippi while it continued its spread in Georgia and South Carolina as well. The detection of the problem in avocado-growing areas of Florida is generating significant concern among commercial growers and residents with avocado yard trees. The detection of laurel wilt in Jackson County, Mississippi reflects a very large geographic jump for the beetle and fungus; it is not known how the problem got there, but human-aided movement or a separate introduction in cargo seem to be more likely causes than “natural” spread. If the beetle had dispersed there on its own, symptoms of laurel wilt would presumably be present in the redbay range between coastal Mississippi and the infested counties in Florida. Please see Laurel Wilt History.

Please view this excellent YouTube presentation Laurel Wilt in Florida and the Power Point presentation: Laurel Wilt on Redbays

Photo by Bettaman

to by Bettaman

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Western Plant Diagnostic Network News

Ronald F. Billings

Photo by Ronald F. Billings

Photo from FL Plant Industry

Photo by S.W. Fraedrich

Photo by Tom Harrington

Photo by Bettaman

Photo by S.W. Fraedrich

Photo by Dr. Jorge Peña

The vector: Redbay Ambrosia Beetle Xyleborus glabratus: top actual size; & bottom close up

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The fungus: Raffaelea lauricola, the causal agent of Laurel wilt

Wilt symptoms of trees attacked by Xyleborus glabratus and infected with Raffaelea lauricola

Redbay cross section showing sapwood discoloration from the

fungus

Avocado tree in Florida killed by the fungus, Raffaelea lauricola Bark removed to show black

discoloration on the sapwood surface of redbay diseased with

Laurel wilt.

Perhaps the strangest sign of Laurel Wilt is the formation of frass-tubes or “toothpicks” that are produced as the beetles bore into the trees,

as seen in the photos left and right.

As trees die they are increasingly attacked by the redbay ambrosia beetle as well as other beetles. Tunnels excavated into these dead and dying trees become “homes” for the ambrosia beetles and significant numbers of offspring are produced in these trees. The redbay ambrosia beetles that emerge from dead and dying redbay trees carry the laurel wilt fungus, and the beetles can spread the fungus to healthy trees, as describe by the diagram on page 5.

Photo by A. Mayfield DOF/DOACS

Photo by S.W. Fraedrich

Photo by S.W. Fraedrich

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Western Plant Diagnostic Network News

Distribution and Spread of Laurel Wilt in the Southeastern US 2004 – 2012

Consequences of Laurel Wilt for the WPDN Region

In the West California is a major producer of commercial of avocados with 66,000 acres located along

the southern coast and coastal valleys, with 60% in San Diego County. Hawaii has 330 acres and Florida

produces 6,800 acres of avocados. The University of California at Riverside and the California

Department of Food and Agriculture are leading the effort to keep laurel wilt out of California. In

addition to avocados, other members of the Lauraceae family are also in danger. These include Bay

laurel (also known as Oregon myrtle and pepperwood) Umbellularia californica, European laurel

Laurus nobilis, and camphor tree Cinnamomum camphora, an ornamental that has become

naturalized in many areas. View the WPDN Power Point presentation: Laurel Wilt from a California

Perspective and the Center for Invasive Species (CISR)UC Riverside pest alert at: Redbay Ambrosia

Beetle and Laurel Wilt

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Western Plant Diagnostic Network News

Photo by Davis L. Magney

Umbellularia californica distribution

Bay Laurel/ Oregon myrtle/Pepperwood U. californica

Culinary herb Laurel Laurus nobilis

Photo from The Garden Web

Camphor tree: Cinnamomum

camphora

Avocado tree: Persea americana

The life-cycle of Laurel Wilt disease caused by the

fungus Raffaelea lauricola and vectored by the redbay ambrosia beetle, Xyleborus

glabratus.

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Western Plant Diagnostic Network News

More of the Same! How a new invasive Ambrosia Beetle is threatening Western Trees

An ambrosia beetle named polyphagous shot hole borer, in the genus Euwallacea , is an invasive pest that attacks oak and avocado trees, causing branch dieback and eventually death. The beetle bores into the trees and spreads a fungus in the genus Fusarium that, in turn, attacks the vascular tissue of the tree and disrupts water and nutrient flow. Both the fungus and the beetle were discovered on several backyard avocado trees in residential neighborhoods and a commercial avocado grove in Los Angeles County in February and March 2012. box elder (Acer negundo), castor bean (Ricinus communis), avocado (Persea americana), English oak (Quercus robur), coast live oak (Quercus agrifolia), big leaf maple (Acer macrophyhllum) silk tree (Albizia julibrissin) Liquidambar (Liquidambar styraciflua), Coral tree (Erythrina coralladendron), Titoki tree (Alectryon excelsus), California sycamore (Platanus racemose) and blue palo verde (Cercidium floridum). (The beetle was previously misidentified as the Tea Shot Hole Borer. But subsequent DNA sequencing at the University of California, Riverside revealed the beetle to be different from the Tea Shot Hole Borer. The name polyphagous shot hole borer has been suggested for the beetle.) No effective solutions for eradicating the beetle have been found. Polyphagous Shot Hole Borer (PSHB) is very small and hard to see. The beetle holes penetrate ~1-4 cm (0.4-1.57 inch) into the wood and there are often many exit holes on an infested tree. Females are black colored and about 1.8 – 2.5 mm (0.07-0.1 inch) long, about the size of a sesame seed. Males are much less common than the females, and rarely found. They are small, wingless and brown colored, about 1.5-1.67 mm (0.06-0.065 inch) long. The exit hole is about 0.85 mm (0.033 inch) in diameter. A new species of Fusarium new species is inoculated into its hosts by the beetle. The fungus destroys the food and water conducting systems of the tree, eventually causing stress and dieback. The larvae of the beetles feed on the fungus within the galleries in infected tree, forming a symbiotic relationship the fungus and beetle.

For more on this vector-spread fungus disease please see: http://cisr.ucr.edu/tea_shot_hole_borer.html

And a pest alert from the Los Angeles County Agricultural Commissioner: http://www.cdfa.ca.gov/plant/PPD/PDF/Euwallacea_sp-Fusarium_sp.pdf

Adult PSHB Larval PSHBs in galleries

Adult PSHBs in galleries in tree

Photo by Akif Eskalen CISR Photo by Akif Eskalen CISR Photo by Akif Eskalen CISR

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Western Plant Diagnostic Network News

Fusarium fungal infections in trees introduced by the Polyphagous Shot Hole Borer (PSHB)

All five photos are courtesy of the Center for Invasive Species Research (CISR) at UC Riverside. Thanks to Mark Hoddle, Gevork Arakelian, and Akif Eskalen of CISR for the research on this new insect vector and new Fusarium species. Please visit their very informative website at: Center for Invasive Species Research

Photo by Akif Eskalen CISR Photo by Chela Ghaly

Pale Cyst Nematode of Potato spreads again in Idaho

On April 19, 2006, officials of USDA’s Animal and Plant Health Inspection Service (APHIS) and the Idaho State Department of Agriculture (ISDA) announced the detection of pale cyst nematode (PCN), Globodera pallida, a major pest of potato crops, in Bingham County (see the Idaho Pale Cyst Nematode report). This was the first detection of the pest in the United States. The nematode cysts were detected during a routine survey of tare soil at an ISDA grader facility in eastern Idaho. Subsequent 2006 surveying to determine the possible origin and distribution of the pest in Idaho confirmed seven PCN-positive fields, all located in close proximity, within Bingham and Bonneville Counties in eastern Idaho. In response to the detection, Canada, Mexico and Korea shut off importation of potatoes from Idaho, while Japan cut off importation of potatoes from the entire U.S causing economic losses. The US exported 1,366,649 metric tons of potatoes valued at $1.35 billion in the 2010-2011 fiscal year. Japan is the largest market with $26 million. It was found that the all eight fields had been farmed by the same operator and was probably spread by contaminated soil clinging to the tractor. The ten PCN-infested fields lie within a roughly three mile radius and the fields associated with them through shared tenancy, farming practices, equipment, and/or shared borders have been extensively surveyed and regulated. Since program inception, a total of 30,917 acres have been regulated due to their infestation or association with an infested field. Non-infested, associated fields have been eligible for federal deregulation following a sequence of soil surveys with no PCN detections. To date, 29,653 acres have been released from federal regulation. Currently, 1,264 acres (only the PCN-infested fields) remain regulated.

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Western Plant Diagnostic Network News

On August 28, 2006, the positive fields and an area surrounding the fields were placed under a Federal Domestic Quarantine Order and parallel State Rule establishing restrictions on planting and interstate/intrastate movement of certain regulated articles from within Idaho in order to prevent the spread of PCN. Starting again in March 2011, infested potato fields were found in Bonneville and Bingham counties. Three more infested fields were found in February 2012 in these same counties. Please see the USDA-APHIS timeline and maps of the PCN. Idaho has 295,000 acres of russet potatoes. Idaho also led the US in certified seed potatoes with 31,000 acres. An interesting fact is the average American eats 130 lbs. of potatoes per year.

Photo by Bonsak Hammeraas

Photo courtesy of the FL Division of Plant Industry

Potato plants infested with pale cyst nematodes, Globodera pallida

Photo courtesy of the FL Division of Plant Industry

Potato tubers infested with PCN

Photo by Bonsak Hammeraas

Potato roots infested with PCN

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Western Plant Diagnostic Network News

And now for some good news!

Six individuals from throughout the NPDN were acknowledged recently with the NPDN Directors Regional Awards. Members of the executive committee nominated individuals from within their respective regions to be recognized for outstanding contributions to the regional and national networks. This year’s recipients are Barry Brennan (University of Hawaii, WPDN), Fred Brooks (University of Hawaii, WPDN), Frank Hale (University of Tennessee, SPDN), Richard “Dick” Hoenisch (University of California, Davis, WPDN), Consuelo Estevez de Jensen (University of Puerto Rico, SPDN), and Karen Snover-Clift (Cornell University, NEPDN). NPDN Executive Director Rick Bostock announced the awards during the NPDN Town Hall at the American Phytopathological Society national meeting in Providence, RI on August 6, 2012.

Our WPDN Awardees

Barry Brennan, Entomologist and Emeritus Professor,

University of Hawaii, Manoa

Fred Brooks, Plant pathologist and disease photographer,

University of Hawaii, Manoa

Dick Hoenisch, Plant pathologist UC Davis and

NPDN and WPDN Training and Education chair and faithful

newsletter editor

Professor Rick Bostock (left), WPDN Director and Plant Pathologist at UC Davis, became a Fellow of the American Phytopathological Society (APS) for

outstanding research, teaching, mentoring, and leadership with UC Davis, the APS, the NPDN, and the

WPDN. The award took place at the APS national meeting in Providence RI. Rick just stepped down as

NPDN executive director after three years of leadership and service. He is being presented with the Fellowship

award by John Sherwood (right) of the University of Georgia. Rick, congratulations on this honor and thanks

for your leadership of the WPDN!

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Western Plant Diagnostic Network News

Meet and Congratulate Maryna Serdani from Oregon State University’s Plant Clinic

Maryna Serdani from Oregon State University’s Plant Clinic is being honored with the 2012 Agriculture Research Foundation Faculty Research Assistant Award. This award recognizes outstanding and exceptional service by Faculty Research Assistants within the College of Agricultural Sciences at Oregon State University. Evaluations are based on job performance and innovation (as it exceeds normal expectations), willingness to accept new responsibilities, peer recognition and evidence of continued professional growth and development. Maryna hails from Stellenbosch, South Africa where she received her Master’s Degree Cum Laude under the supervision of Pedro Crous (current Director of CBS Fungal Bio-diversity Centre, The Netherlands). She and her family moved to the United States in 2003, where she started her OSU career, focusing on research in post-harvest tree-fruit pathology at the Mid-Columbia Agricultural Research and Extension Center in Hood River, OR. In 2007, Maryna joined the OSU Plant Clinic as plant disease diagnostician and Senior FRA with Melodie Putnam (Plant Clinic Director). More recently, Maryna temporarily took over the duties of Director while Melodie was on a year-long sabbatical. During this time, Maryna diagnosed around 2,000 samples and detected nine new pathogens and pests, some of which were of regulatory significance. She has also developed a rapid and accurate molecular assay (LAMP) for detection of the bacterial pathogen Rhodococcus fascians that she demonstrated at a hands-on workshop of diagnosticians from across the country at the annual meeting of the National Plant Diagnostic Network (NPDN) in Berkeley last November.

The University of California Agriculture and Natural Resources (UCANR) recently published a second edition of IPM in Practice: Principles and Methods of Integrated Pest Management. This manual from the University of California Statewide IPM Program is the most comprehensive, practical field guide ever developed for setting up and carrying out an IPM program in any type of crop or landscape. Now completely in color with more than 160 color photos and 100 hand-drawn color illustrations, this manual is the official study guide for individuals preparing for the California Department of Pesticide Regulation's Pest Control Adviser exam. At more than 290 pages, this manual is now available for purchase for $35.00 at ucanr.edu/ipmpractice. If you are interested in purchasing this manual, please feel free to contact Marissa Palin: 530 754 3934 mpalin@ucanr.edu . Volume discounts will apply on orders of 10 or more.

IPM in Practice features IPM strategies for weed, insect, pathogen, nematode, and vertebrate pests and provides specific information on how to set up sampling and monitoring programs in the field. This manual covers methods applicable to vegetable, field, and tree cops as well as landscape and urban situations. Designed to bring you the most up-to-date research and expertise, this manual draws on the knowledge of dozens of experts within the University of California, public agencies, and private practice.