DOCSLIB.ORG

National Pest Alert – Thousand Cankers Disease of Walnut

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
National Pest Alert – Thousand Cankers Disease of Walnut NationalNational PestPest AlertAlert Thousand Cankers Disease of Walnut Distribution and Transmission these insect-vectored diseases only require one introduction of the fungus into the tree Thousand cankers disease (TCD) is caused by a fungus (Geosmithia and then the fungus spreads through the morbida) that is vectored by the walnut twig beetle (Pityophthorus whole tree becoming systemic and even able juglandis). It is unknown if G. morbida is native to North America. to spread through root grafts. TCD requires The walnut twig beetle is native to North America and was first re- multiple introductions by the beetle. corded feeding on Arizona walnut (Juglans major) in the southwest- ern U.S., but it is not harmful to Arizona walnut. The walnut twig Host Plants beetle has expanded its host range to other species of walnut includ- ing black walnut, which is not native to western states. TCD was TCD affects many walnut trees (Juglans Windham Alan courtesy confined to western spp.) and species vary in their susceptibil- Figure 2. Microscopic states (California, ity to TCD, but black walnut (Juglans nigra) view of the conidiophores Oregon, Washing- is very susceptible. Black walnut is an and conidia of ton, Idaho, Utah, important tree in the forest ecosystem and Geosmithia morbida. New Mexico, Colo- landscape, and is highly valued for lumber, rado and Arizona) veneer and nut production. until 2010 when the disease was found Symptoms in the native range of black walnut. It A black walnut tree can be infected with is unknown how TCD for many years before showing widespread the symptoms, but once branch dieback appears Windham Mark courtesy disease will become the tree rapidly declines and dies within a Figure 3. The yellowish- or the long-term few years. The first symptom to appear is brown walnut twig beetle courtesy Alan Windham Alan courtesy effects on black flagging leaves (leaves wilting and yellow- is less than 2 mm in Figure 1. Walnut trees killed by Thousand walnut. The beetles ing mid-summer) followed by thinning of length with 4-6 broken Cankers Disease in Knox County, TN. carry the fungal the canopy from twig and branch dieback. grooves near its head spores (conidia) on their bodies and transfer the spores to trees Eventually the whole tree dies as thousands (asperities), yellow hairs when they tunnel into the branches or trunk. of cankers girdle branches and the trunk. (setae) on its head and Symptoms of TCD include: a sharp angle to its Biology • Flagging leaves (Fig. 7) posterior (steep • Wilting of foliage (Fig. 8) declivity of The fungus invades the phloem tissue located just beneath the bark • Branch dieback elytra). and kills it. This darkened, dead (necrotic) tissue is called a canker. • Thinning canopy (Fig. 9). Cankers caused by G. morbida are small, but repeated feeding and • Epicormic shoots (water spouts) (Fig. 9) egg laying by the walnut twig beetles lead to the introduction of • Cankers under the bark (Figs. 5 and 6) the fungus into multiple areas on the same tree. Numerous can- • Dying tree (Fig. 1) kers girdle and kill branches and/or the whole tree by halting the normal flow of nutrients. Essentially the tree is killed by thousands of cankers. This is very different from Dutch elm disease or oak wilt; courtesy Mark Windham Mark courtesy Figure 4. Walnut twig beetle feeding tunnels and emergence holes. Management of TCD in the trees and is not seed-borne. Do not move walnut wood across state lines with- The symptoms of TCD on black walnut out checking for state quarantines that have are similar to other common diseases of been instituted to prevent infected walnut Windham Mark courtesy walnut as well as decline from other causes, from moving into the state. Figure 7. Flagging (yellowing) of foliage particularly environmental stresses. It is im- If you have a walnut tree exhibiting signs of is an early symptom of thousand cankers portant to evaluate the whole tree and make disease. a proper diagnosis. There are no manage- decline it is important to contact your state ment options for the disease or the beetle at extension service. Do not mail samples to this time and future control options will be a diagnostic laboratory without contacting limited due to the tree producing an edible them first to receive packaging instructions nut. to prevent beetle emergence during ship- ment. Preventing the Spread of TCD TCD can be spread by moving walnut wood Contributing Authors: Laura Jesse, Plant for woodworking or as firewood. Nuts are & Insect Diagnostic Clinic, Iowa State not a concern since TCD is not systemic University; Mark Windham, Department of Windham Mark courtesy Entomology and Plant Pathology, Univer- Figure 8. Check wilted branches for walnut sity of Tennessee; Alan Windham, Depart- twig beetles. ment of Entomology and Plant Pathology, University of Tennessee; Jesse Randall, This publication was produced and distrib- Department of Natural Resources Ecology uted in cooperation with the USDA NIFA Management, Iowa State University; Mark Integrated Pest Management Program, the Shour, Department of Entomology, Iowa North Central IPM Center and the Land State University; Donald Lewis, Department Grant Universities. For more information of Entomology, Iowa State University; Mark about the development of this pest alert or Gleason, Department of Plant Pathology, to obtain copies, contact Susan Ratcliffe at Iowa State University [email protected] or by phone at 217- courtesy Mark Windham Mark courtesy 333-9656. Figure 5. Canker damage to cambium and phloem tissues due to infection of Geosmithia morbida on black walnut tree. courtesy Alan Windham Alan courtesy Figure 9. Thousand cankers disease can lead to shrinkage of canopy (dead courtesy Mark Windham Mark courtesy limbs) and a profusion of water spouts Figure 6. Numerous cankers can be found close to each other in the (epicormic shoots). same limb..
Load more

Recommended publications
  • Annotated Check List and Host Index Arizona Wood
    Annotated Check List and Host Index for Arizona Wood-Rotting Fungi Item Type text; Book Authors Gilbertson, R. L.; Martin, K. J.; Lindsey, J. P. Publisher College of Agriculture, University of Arizona (Tucson, AZ) Rights Copyright © Arizona Board of Regents. The University of Arizona. Download date 28/09/2021 02:18:59 Link to Item http://hdl.handle.net/10150/602154 Annotated Check List and Host Index for Arizona Wood - Rotting Fungi Technical Bulletin 209 Agricultural Experiment Station The University of Arizona Tucson AÏfJ\fOTA TED CHECK LI5T aid HOST INDEX ford ARIZONA WOOD- ROTTlNg FUNGI /. L. GILßERTSON K.T IyIARTiN Z J. P, LINDSEY3 PRDFE550I of PLANT PATHOLOgY 2GRADUATE ASSISTANT in I?ESEARCI-4 36FZADAATE A5 S /STANT'" TEACHING Z z l'9 FR5 1974- INTRODUCTION flora similar to that of the Gulf Coast and the southeastern United States is found. Here the major tree species include hardwoods such as Arizona is characterized by a wide variety of Arizona sycamore, Arizona black walnut, oaks, ecological zones from Sonoran Desert to alpine velvet ash, Fremont cottonwood, willows, and tundra. This environmental diversity has resulted mesquite. Some conifers, including Chihuahua pine, in a rich flora of woody plants in the state. De- Apache pine, pinyons, junipers, and Arizona cypress tailed accounts of the vegetation of Arizona have also occur in association with these hardwoods. appeared in a number of publications, including Arizona fungi typical of the southeastern flora those of Benson and Darrow (1954), Nichol (1952), include Fomitopsis ulmaria, Donkia pulcherrima, Kearney and Peebles (1969), Shreve and Wiggins Tyromyces palustris, Lopharia crassa, Inonotus (1964), Lowe (1972), and Hastings et al.
    [Show full text]
  • Incidence, Dispersal, and Risk Assessment of Walnut Twig Beetle, Pityophthorus Juglandis, on Black Walnut in Appalachian Forests
    University of Tennessee, Knoxville TRACE: Tennessee Research and Creative Exchange Masters Theses Graduate School 8-2018 Incidence, Dispersal, and Risk Assessment of Walnut Twig Beetle, Pityophthorus juglandis, on Black Walnut in Appalachian Forests Philip Gerald Hensley University of Tennessee, [email protected] Follow this and additional works at: https://trace.tennessee.edu/utk_gradthes Recommended Citation Hensley, Philip Gerald, "Incidence, Dispersal, and Risk Assessment of Walnut Twig Beetle, Pityophthorus juglandis, on Black Walnut in Appalachian Forests. " Master's Thesis, University of Tennessee, 2018. https://trace.tennessee.edu/utk_gradthes/5177 This Thesis is brought to you for free and open access by the Graduate School at TRACE: Tennessee Research and Creative Exchange. It has been accepted for inclusion in Masters Theses by an authorized administrator of TRACE: Tennessee Research and Creative Exchange. For more information, please contact [email protected]. To the Graduate Council: I am submitting herewith a thesis written by Philip Gerald Hensley entitled "Incidence, Dispersal, and Risk Assessment of Walnut Twig Beetle, Pityophthorus juglandis, on Black Walnut in Appalachian Forests." I have examined the final electronic copy of this thesis for form and content and recommend that it be accepted in partial fulfillment of the equirr ements for the degree of Master of Science, with a major in Entomology and Plant Pathology. Jerome F. Grant, Major Professor We have read this thesis and recommend its acceptance: Paris L. Lambdin, Gregory J. Wiggins, Mark T. Windham Accepted for the Council: Dixie L. Thompson Vice Provost and Dean of the Graduate School (Original signatures are on file with official studentecor r ds.) Incidence, Dispersal, and Risk Assessment of Walnut Twig Beetle, Pityophthorus juglandis, on Black Walnut in Appalachian Forests A Thesis Presented for the Master of Science Degree The University of Tennessee, Knoxville Philip Gerald Hensley August 2018 Copyright © 2018 by Philip Hensley All rights reserved.
    [Show full text]
  • Thousand Cankers Disease
    Species Brief 5.6 What Is in Your Firewood? Thousand Cankers Disease Pest and Target Species Identification and Symptoms Thousand cankers disease (TCD) is caused The walnut twig beetle is approximately one- by the interaction between the walnut twig sixteenth of an inch long, and yellowish brown beetle, Pityophthorus juglandis (Coleoptera: to dark brown in color (Figure 1). A black walnut Curculionidae: Scolytinae), and a fungus, tree can be infected with TCD for many years Geosmithia morbida. The twig beetle is the only before showing symptoms. Not easily detected, known vector of this fungus, which can attack this insect bores into the host tree, creating the eastern species of the black walnut. The galleries (tunnel-like paths) underneath the black walnut has little to no resistance to the bark (Figure 2). The beetle carries a harmful disease. fungus on its body that spreads, causing can- kers to form in these galleries (Figure 3). The cankers expand and combine to girdle infected Range branches, disrupting the flow of water and The walnut twig beetle is native to the western nutrients. The leaves will yellow, wilt rap- United States and Mexico. Geosmithia morbida idly, and turn brown. Stem dieback or branch is also believed to be native to southwestern mortality occurs in the crown. Numerous tiny North America. This insect and fungus com- entrance and exit holes created by adult beetles plex was first identified east of the Mississippi are noticeable on dead and dying branches. Tree River in Tennessee in 2010. By the end of 2011 it mortality typically occurs approximately three had been found in Virginia and Pennsylvania.
    [Show full text]
  • Vascular Plant and Vertebrate Inventory of Fort Bowie National Historic Site Vascular Plant and Vertebrate Inventory of Fort Bowie National Historic Site
    Powell, Schmidt, Halvorson In Cooperation with the University of Arizona, School of Natural Resources Vascular Plant and Vertebrate Inventory of Fort Bowie National Historic Site Vascular Plant and Vertebrate Inventory of Fort Bowie National Historic Site Plant and Vertebrate Vascular U.S. Geological Survey Southwest Biological Science Center 2255 N. Gemini Drive Flagstaff, AZ 86001 Open-File Report 2005-1167 Southwest Biological Science Center Open-File Report 2005-1167 February 2007 U.S. Department of the Interior U.S. Geological Survey National Park Service In cooperation with the University of Arizona, School of Natural Resources Vascular Plant and Vertebrate Inventory of Fort Bowie National Historic Site By Brian F. Powell, Cecilia A. Schmidt , and William L. Halvorson Open-File Report 2005-1167 December 2006 USGS Southwest Biological Science Center Sonoran Desert Research Station University of Arizona U.S. Department of the Interior School of Natural Resources U.S. Geological Survey 125 Biological Sciences East National Park Service Tucson, Arizona 85721 U.S. Department of the Interior DIRK KEMPTHORNE, Secretary U.S. Geological Survey Mark Myers, Director U.S. Geological Survey, Reston, Virginia: 2006 For product and ordering information: World Wide Web: http://www.usgs.gov/pubprod Telephone: 1-888-ASK-USGS For more information on the USGS-the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment: World Wide Web:http://www.usgs.gov Telephone: 1-888-ASK-USGS Suggested Citation Powell, B. F, C. A. Schmidt, and W. L. Halvorson. 2006. Vascular Plant and Vertebrate Inventory of Fort Bowie National Historic Site.
    [Show full text]
  • Riparian Plants in the Southwestern United States
    Phenology and Stand Composition of Woody Riparian Plants in the Southwestern United States Item Type Article Authors Brock, John H. Publisher University of Arizona (Tucson, AZ) Journal Desert Plants Rights Copyright © Arizona Board of Regents. The University of Arizona. Download date 07/10/2021 05:55:16 Link to Item http://hdl.handle.net/10150/554241 Brock Riparian Plants 23 species were observed monthly (bimonthly in summer) at six Phenology and Stand sites in eastern Arizona and New Mexico. Phenologi- cal events were placed into eight categories for data collection. Stand composition data was collected from four randomly lo- Composition of Woody cated macroplots at each site in the summer of 1983. Weather data for the period of study was summarized for the region. Riparian Plants in the Four general phenology groups were identified: 1) spring flow- ering and fruit dispersal as characterized by Fremont cotton- Southwestern United wood (Populus fremontii) and Goodding willow (Salix gooddingii), 2) Spring flowering/autumn -winter fruit dispersal characterized by box elder (Acer negundo var. interius), netleaf States hackberry (Celtis reticulata), Arizona sycamore (Plantanus wrightii), and velvet ash (Fraxinuspennsylvanica ssp. velutina), 3) Spring flowering and late summer fruit dispersal demon- strated by Arizona walnut (Juglans major), and 4) Multidate flowering and fruit dispersal displayed by velvet mesquite (Prosopis velutina). Fremont cottonwood and Goodding wil- low dominated the sites, while netleaf hackberry, box elder, velvet
    [Show full text]
  • Analysis of Phylogenetic Relationships in the Walnut Family Based on Internal Transcribed Spacer Sequences and Secondary Structures(ITS2)
    Analysis of Phylogenetic Relationships in The Walnut Family Based on Internal Transcribed Spacer Sequences and Secondary Structures(ITS2) Zhongzhong Guo Tarim University Qiang Jin Tarim University Zhenkun Zhao Tarim University Wenjun Yu Tarim University Gen Li Tarim University Yunjiang Cheng Tarim University Cuiyun Wu Tarim University rui Zhang ( [email protected] ) Tarim University https://orcid.org/0000-0002-4360-5179 Research Article Keywords: Base sequence, Evolution, Juglandaceae, Ribosomal spacer, Secondary structure Posted Date: May 13th, 2021 DOI: https://doi.org/10.21203/rs.3.rs-501634/v1 License: This work is licensed under a Creative Commons Attribution 4.0 International License. Read Full License Page 1/23 Abstract This study aims to investigate the phylogenetic relationships within the Juglandaceae family based on the Internal Transcribed Spacer's primary sequence and secondary structures (ITS2). Comparative analysis of 51 Juglandaceae species was performed across most of the dened seven genera. The results showed that the ITS2 secondary structure's folding pattern was highly conserved and congruent with the eukaryote model. Firstly, Neighbor-joining (N.J.) analysis recognized two subfamilies: Platycaryoideae and Engelhardioideae. The Platycaryoideae included the Platycaryeae (Platycarya+ (Carya+ Annamocarya)) and Juglandeae (Juglans-(Cyclocarya + Pterocarya)). The Engelhardioideae composed the (Engelhardia+Oreomunnea+Alfaroa)). The Rhoiptelea genus was generally regarded as an outgroup when inferring the phylogeny of Juglandaceae. However, it is clustered into the Juglandaceae family and showed a close relationship with the Platycaryoideae subfamily. Secondly, the folded 3-helices and 4-helices secondary structure of ITS2 were founded in the Juglandaceae family. Therefore, these ITS2 structures could be used as formal evidence to analyze Juglandaceae's phylogeny relationship.
    [Show full text]
  • Walnut Thousand Cankers Disease Alert
    Walnut Thousand Cankers Disease Alert Mary Ann Hansen1 and Elizabeth Bush1, Extension Plant Pathologists Eric Day1, Extension Entomologist Gary Griffin1, Forest Pathologist Norm Dart2, State Plant Pathologist 1Virginia Tech, 2Virginia Department of Agriculture and Consumer Services First occurrence of Thousand Cankers Disease of Black Walnut (Juglans nigra) in Virginia: On June 24th, 2011, the first case of thousand cankers disease of black walnut was found in two trees with severe epicormic branching on the lower trunk and advanced decline in Chesterfield County, Virginia. Presence of the vector and pathogen associated with this disease, the walnut twig beetle (Pityophthorus juglandis) and the fungus Geosmithia morbida, was confirmed in the samples. This is the first report of thousand cankers disease of black walnut in Virginia. The Virginia Department of Agriculture and Consumer Services (VDACS) is conducting a delimiting survey to determine the extent of the infestation surrounding the positive find. Initial delimiting survey work has found additional trees with thousand cankers disease in Chesterfield and Henrico Counties. The first report of thousand cankers disease of black walnut east of the Mississippi River (http://news.tennesseeanytime.org/node/5684) was previously reported when the Tennessee Department of Agriculture announced the occurrence of the disease in black walnut trees in Knox County, Tennessee in August 2010. Although this lethal disease has been present in parts of the western U. S. for at least a decade, it had not previously been reported east of the Mississippi River in the native range of the black walnut. The presence of this devastating disease in the southeastern U.
    [Show full text]
  • Thousand Cankers Disease of Black Walnut
    UI Extension Forestry Information Series II Insects and Diseases No. 14 Thousand Cankers Disease on Black Walnut Yvonne Barkley This story begins in the summer of 2005. A land- Samples were collected and brought back to the owner in Emmett, ID reported black walnut (Jug- University of Idaho for identifi cation of the insect lans nigra) trees dying. The tree would look fi ne involved. Dr. Stephen Cook, University of Idaho and until the hot weather hit, and then the foliage Insect Ecologist, and Frank Merikel, Manager would quickly wilt and the tree would die. The of the University of Idaho William Barr Insect symptoms progresses quickly, with some trees Museum, concurred that the insect involved was dying in as little as one month. Another call came NOT Ambrosia beetles, but instead was the wal- in that same year from Meridan, ID – same thing. nut twig beetle (Pityophthorus juglandis), a native The next year, the same patterns of symptoms be- bark beetle on black walnut in New Mexico and gan to be reported in Boise. Initially, the common Arizona. thought was that trees had suffered many years of drought stress and had fi nally succumbed to While searching for information on this beetle, I the lack of suffi cient moisture. But as landown- came across an article from Boulder, CO, and the ers and resource managers began to look more description and photos matched what we were closely at the affected trees they found that there seeing here exactly. I contacted Dr. Ned Tisserat, were large numbers of very small holes in the Plant Pathologist at Colorado State University, bark, which were initially thought to be Ambro- and the story he told me was the same as ours.
    [Show full text]
  • Ethnobotanical Survey of Medicinal Plants Used by the Natives of Umuahia, Abia State, Nigeria for the Management of Diabetes
    IOSR Journal Of Pharmacy And Biological Sciences (IOSR-JPBS) e-ISSN:2278-3008, p-ISSN:2319-7676. Volume 14, Issue 5 Ser. I (Sep – Oct 2019), PP 05-37 www.Iosrjournals.Org Ethnobotanical Survey of Medicinal Plants Used By the Natives of Umuahia, Abia State, Nigeria for the Management of Diabetes Anowi Chinedu Fredrick1 , Uyanwa Ifeanyi Christian1 1 Department of Pharmacognosy and Traditional Medicine, Faculty of Pharmaceutical Sciences, Nnamdi Azikiwe University, Awka, Nigeria. Corresponding Author: Anowi Chinedu Fredrick Abstract: Diabetes has been regarded as one of the major health problems wrecking havoc on the people especially the geriatrics. In Umuahia, diabetes is regarded as a serious health problems with high rate of mortality, morbidity and with serious health consequences. Currently plants are used by the natives to treat this disease. Hence the need for this study to ascertain medicinal plants with high cure rate but little side effects as synthetic antidiabetic drugs have been known to be associated with various serious and deleterious side effects. This is therefore a field trip conducted in Umuahia, Nigeria, to determine the various medicinal plants used by the natives in the management of diabetes. Dialogue in the form of semi-structured interview was conducted with the traditional healers (TH). Some of whom were met many times depending on the amount of information available at any given time and to check the already collected information. Information regarding the plants used in the management /treatment of diabetes were collected, the socio-political data of the THs, formulation of remedies, and the symptoms and other ways the THs use to diagnose diabetes.
    [Show full text]
  • Pest Alert – Walnut Twig Beetle and Thousand Cankers Disease Of
    Pest Alert Walnut Twig Beetle and Thousand Cankers Disease of Black Walnut For at least the past decade, an unusual decline of black walnut (Juglans nigra) has been observed in several western states. Initial symptoms involve a yellowing and thinning of the upper crown, which progresses to include death of progressively larger branches (Figure 1). During the final stages large areas of foliage may rapidly wilt. Trees often are killed within three years after initial symptoms are noted. Tree mortality is the result of attack by the walnut twig beetle (Pityophthorus juglandis) and subsequent canker development around beetle galleries caused by a fungal associate (Geosmithia sp.) of the beetle (Figure 2). The name for this insect- Figure 2. Outer bark peeled from a log to expose disease complex is thousand Figure 1. Rapidly wilting black walnut coalescing branch cankers produced by Geosmithia cankers disease (TCD) of in the final stage of thousand cankers morbida. disease. walnut. Walnut Twig Beetle Distribution. The walnut twig beetle is native to North America and was originally described in 1928 based on specimens collected in the area of “Lone Mountain”, New Mexico (Grant County). In the 1992 catalog of Bark and Ambrosia Beetles by Wood and Bright the primary range of the insect was listed to include New Mexico, Arizona, and Chihuahua, Mexico (Figure 3). This range appears to coincide largely with the distribution Figure 3. Distribution of the walnut twig beetle. In green are states and the California of Arizona walnut (J. major), the county of Los Angeles with records of the species prior to 1960.
    [Show full text]
  • Bark and Ambrosia Beetles and Their Associated Fungi Colonizing
    Walnut Council Bulletin Promoting Walnut and Other Fine Hardwoods Volume 40, Number 2 ISSN 1041-5769 June 2013 Walnut Council State Chapter Reports Bark and Ambrosia Beetles and Their Associated Fungi Colonizing Stressed Walnut in Missouri and Indiana Missouri Chapter Indiana Chapter Report The Missouri Chapter of the Walnut Council had its spring The Indiana Chapter met on April 20th at the Bill By Dr. Sharon Reed and Dr. James English, post-doctoral fellow In addition to walnut twig beetles, there are many other types meeting on Friday and Saturday, May 10 & 11 at member’s Rodecker property in central Indiana with 34 in and professor of the University of Missouri Plant Sciences of bark- and wood-boring beetles that create egg galleries in properties in central Missouri. On Friday, the 32 attendees attendance. The sessions were led by Lenny Farlee Division, Dr. Jennifer Juzwik, forest pathologist of the Forest black walnut trees. Most of these beetles carry fungi on their carpooled to the Fred Crouse property. Management of (Purdue University extension), and Phil O’Connor Service Northern Research Station, and Dr. Matt Ginzel, bodies, some of which can be pathogenic to trees. Researchers mainly white and red oak was discussed along with the past (Indiana Division of Forestry). The 10 year old planting associate professor of the Purdue Department of Entomology at the University of Missouri, Purdue University and the Forest management history and plans for the future. featured over 2,000 walnut trees with some single and Service have teamed up to investigate which bark and ambrosia Thousand cankers disease (TCD) is a growing threat to black double row white pine borders.
    [Show full text]
  • Status and Impact of Walnut Twig Beetle in Urban Forest, Orchard, and Native Forest Ecosystems
    J. For. 117(2):152–163 BARK BEETLE SPECIAL SECTION doi: 10.1093/jofore/fvy081 Published by Oxford University Press on behalf of the Society of American Foresters 2019. Tis work is written by (a) US Government employee(s) and is in the public domain in the US. entomology Status and Impact of Walnut Twig Beetle in Urban Forest, Orchard, and Native Forest Ecosystems Steven J. Seybold, William E. Klingeman III, Stacy M. Hishinuma, Tom W. Coleman, and Andrew D. Graves The walnut twig beetle, a native phloem-boring bark beetle originating on Arizona walnut, has invaded urban, is fatal to walnut trees (Figure 2) and was frst orchard, and native forest habitats throughout the USA as well as in Italy. Although the beetle has been associated noted in the late 2000s for its involvement with dead and dying walnut trees indigenous to riparian forests of the Southwest, the primary impact appears to in the gradual deterioration and mortality of have been on the health of landscape black walnut trees in urban and peri-urban sites in western US states, and several species of black walnut in the west- in Pennsylvania, Tennessee, and Virginia. This has been refected in numbers of trees removed and tree removal ern United States (Graves et al. 2009, Flint costs. In addition, trees have been killed in the primary US Juglans germplasm repository in northern California, et al. 2010, Tisserat et al. 2011, Seybold and low, but measureable, tree mortality has occurred in some English walnut orchards in California’s Central Valley. et al. 2013b).
    [Show full text]