Ned Klopfenstein

US Forest Service | FS · Rocky Mountain Research Station

The rust fungus, Puccinia psidii, is a devastating pathogen of introduced eucalypts (Eucalyptus spp.) in Brazil where it was first observed in 1912. This pathogen is hypothesized to be endemic to South and Central America and to have first infected eucalypts via a host jump from native guava (Psidium guajava). Ten microsatellite markers were used t...

Armillaria species display diverse ecological roles ranging from beneficial saprobe to virulent pathogen. Armillaria solidipes (formerly A. ostoyae), a causal agent of Armillaria root disease, is a virulent primary pathogen with a broad host range of woody plants across the Northern Hemisphere. This white-rot pathogen grows between trees as rhizomo...

2017): Insights into the phylogeny of Northern Hemisphere Armillaria: Neighbor-net and Bayesian analyses of translation elongation factor 1-α gene sequences, Mycologia To link to this article: http://dx.

Climate change and associated disturbances are expected to exacerbate forest root diseases because of altered distributions of existing and emerging forest pathogens and predisposition of trees due to climatic maladaptation and other disturbances. Predictions of suitable climate space (potential geographic distribution) for forest pathogens and hos...

Armillaria root disease, caused by diverse species from the Agaricomycete genus Armillaria s.l. (including the closely related genus Desarmillaria), is a primary cause of mortality and growth loss of widely ranging horticultural, urban, and forest trees and shrubs in diverse boreal, temperate, and tropical/subtropical regions where woody plants gro...

Fusaria can be introduced into novel landscapes through latent-infected nursery stock and cause seedling mortality. Molecular tools can rapidly identify and track Fusarioid pathogens to mitigate novel pathogen introductions by informing both pathogen composition and pathogenicity of different Fusarium spp. Understanding the community structure and...

Introduction Cronartium ribicola is an invasive forest pathogen that causes white pine blister rust, which threatens the health and productivity of five-needled white pines including iconic species, such as western white pine (WWP; Pinus monticola) and whitebark pine (WBP; P. albicaulis) in western North America. The pathogen has invaded most of th...

The virulent root disease pathogen Armillaria solidipes causes a white rot of conifers in the western USA, leading to tree mortality and altering forest structure. Few effective methods are available for managing Armillaria root disease on the landscape scale. While previous studies have indicated the potential for the soil microbial community, inc...

Introduction Western white pine (WWP; Pinus monticola) is a keystone species in moist forests of western North America that displays adaptation to ranging climates and resilience to native root diseases. Since Cronartium ribicola, the cause of white pine blister rust (WPBR), was introduced to North America in the early 1900s, WBPR has caused dramat...

Leptographium wageneri is a native fungal pathogen in western North America that causes black stain root disease (BSRD) of conifers. Three host-specialized varieties of this pathogen were previously described: L. wageneri var. wageneri on pinyon pines (Pinus monophylla and P. edulis); L. wageneri var. ponderosum, primarily on hard pines (e.g., P. p...

Armillaria altimontana is a fungus (Basidiomycota, Agaricomycetes, Agaricales, and Physalacriaceae) that is generally considered as a weak/opportunistic pathogen or saprophyte on many tree hosts. It widely occurs across the northwestern USA to southern British Columbia, Canada, but relatively little is known about its ecological role in the diverse...

Diverse fungi collected from symptomatic fruit, stem and branch tissues of Theobroma cacao in five T. cacao-producing localities or municipalities of Mérida State, Venezuela, were identified using both morphological methods and sequencing of multiple loci (ITS, LSU, SSU, TEF1, BTUB, RPB2). Cophinforma atrovirens, Lasiodiplodia brasiliensis and Hypo...

Introduction Fusarioid fungi that cause damping-off and root diseases can result in significant losses to conifer crops produced in forest nurseries across the USA. These nurseries are vital to reforestation and forest restoration efforts. Understanding the diversity of Fusarioid fungi associated with damping-off and root diseases of conifer seedli...

Armillaria root disease is among the largest causes of mortality and lost productivity of widely ranging horticultural, urban, and forest trees/shrubs in diverse boreal, temperate, and tropical regions around the world (Kim et al. 2022). Damage from Armillaria root disease will likely increase in response to changing climate and extreme weather bec...

Introducción: La identificación de las especies de Armillaria y Desarmillaria asociadas con la pudrición de raíces por Armillaria es importante para determinar estrategias de manejo, debido a su variación en patogenicidad y virulencia. Objetivo: Identificar las especies de Desarmillaria/Armillaria asociadas con árboles de litchi (Litchi chinensis S...

Brown root rot disease (BRRD), caused by Phellinus noxius, is an important tree disease in tropical/subtropical areas. To improve chemical control of BRRD and deter emergence of fungicide resistance in P. noxius, this study investigated control efficacies and systemic activities of fungicides with different modes of action. Fourteen fungicides with...

Phellinus noxius is a fungus that causes brown root rot disease in tree and shrub species of subtropical and tropical regions. It has infected and rapidly killed hundreds of important tree and shrub species in these regions. It is widespread in the Pacific Region including all the island states of American Samoa, the Federated States of Micronesia...

Molecular genetics studies provide critical information to establish the scientific foundation for many conclusions reached about Phellinus noxius. The following are some of the more important conclusions being drawn from these studies: • DNA sequencing provides a reliable method to identify P. noxius. • P. noxius possesses considerable genetic var...

Celtis laevigata (sugarberry, southern hackberry) is an important, shade-tolerant, deciduous hardwood tree species that occurs naturally in flood plains, along streams and rivers, and in urban landscapes of the southeastern USA (Kennedy 1990). In recent years, dieback and mortality of C. laevigata have been commonly observed in some areas of South...

Armillaria species show considerable variation in ecological roles and virulence, from mycorrhizae and saprophytes to important root pathogens of trees and horticultural crops. We studied two Armillaria species that can be found in coniferous forests of northwestern USA and southwestern Canada. Armillaria altimontana not only is considered as a wea...

Emerging plant pathogens have been increasing exponentially over the last century. To address this issue, it is critical to determine whether these pathogens are native to ecosystems or have been recently introduced. Understanding the ecological and evolutionary processes fostering emergence can help to manage their spread and predict epidemics/epi...

Emerging plant pathogens have been increasing exponentially over the last century. To address this issue, it is critical to determine whether these pathogens are native to ecosystems or have been recently introduced. Understanding the ecological and evolutionary processes fostering emergence can help to manage their spread and predict epidemics/epi...

Armillaria species show considerable variation in ecological roles and virulence, from mycorrhizae and saprophytes to important root pathogens of trees and horticultural crops. We studied two Armillaria species that can be found in coniferous forests of northwestern USA and southwestern Canada. Armillaria altimontana is considered as a weak, opport...

This Scots pine blister rust (caused by Cronartium pini) recovery plan is one of several plant disease-specific documents produced as part of the National Plant Disease Recovery System (NPDRS) requested by the Homeland Security Presidential Directive Number 9 (HSPD-9). The purpose of the NPDRS is to ensure that the tools, infrastructure, communicat...

Fusarium spp. comprise diverse plant pathogens, which affect both agriculturally and ecologically important plant species, and harmless saprobes. Fusarium spp. inhabit widely ranging, geographic regions across the globe and can be found in soil or plant tissue in every climate type, ranging from tropical to polar regions. In their native habitats,...

Emerging pathogens have been increasing exponentially over the last century. The knowledge on whether these organisms are native to ecosystems or have been recently introduced is often of great importance. Understanding the ecological and evolutionary processes promoting emergence can help to control their spread and forecast epidemics. Using restr...

Desarmillaria caespitosa, a North American vicariant species of European D. tabescens, is redescribed in detail based on recent collections from the USA and Mexico. This species is characterized by morphological features and multilocus phylogenetic analyses using portions of nuc rDNA 28S (28S), translation elongation factor 1-alpha (tef1), the seco...

Myrtle rust (MR) caused by Austropuccinia psidii is one of the most important diseases affecting eucalypt (Eucalyptus) plantations in Brazil. Over the years, selection and planting of MR‐resistant clones has been the primary strategy for MR management. In May 2013, young trees of the GG100 hybrid (E. grandis × E. urophylla) clone—widely planted in...

Populus trichocarpa Torr. and Gray (black cottonwood) is an economically and ecologically important tree species native to western North America. It serves as a model tree species in biology and genetics due to its relatively small genome size, rapid growth, and early reproductive maturity (Jansson and Douglas 2007). Black cottonwood is susceptible...

Root disease pathogens, including Armillaria, are a leading cause of growth loss and tree mortality in forest ecosystems of North America. Armillaria spp. have a wide host range and can cause significant reductions in tree growth that may lead to mortality. DNA sequence comparisons and phylogenetic studies have allowed a better understanding of Arm...

The forest pathology paradigm that one disease is caused by one pathogen is shifting toward a consideration of the complex ecological interactions among pathogens, microbial communities, tree host, and environment. Currently, rapidly evolving technologies have increasing potential to provide a wealth of novel information on complex ecological inter...

Armillaria root and butt diseases, which are a global issue, can be influenced by changing environmental conditions. Armillaria gallica is a well-known pathogen of diverse trees worldwide (Brazee and Wick 2009). Besides A. gallica causing root rot of Hemerocallis sp. and Cornus sp. in South Carolina (Schnabel et al. 2005), little is reported on the...

Background: Development and application of DNA-based methods to distinguish highly virulent isolates of Fusarium oxysporum f. sp. koae [Fo koae; cause of koa wilt disease on Acacia koa (koa)] will help disease management through early detection, enhanced monitoring, and improved disease resistance-breeding programs. Results: This study presents who...

In July-August 2019, seven Armillaria isolates (derived from rhizomorphs and mycelial fans of infected roots) were collected in association with woody hosts in the central Mexico: states of Guanajuato (MEX204), Jalisco (MEX206, MEX208, MEX209), and Michoacan (MEX211, MEX214, MEX216). All seven isolates were identified as Armillaria gallica based on...

Recent taxonomic investigation into genus Pyrrhoderma has determined that the genus currently contains six species, including Pyrrhoderma noxium (formerly Phellinus noxius), and one unnamed, but likely novel species (Zhou et al. 2018). Pyrrhoderma noxium is considered one of the most important pathogens in this genus due to its worldwide distributi...

Phellinus noxius is a root-decay pathogen with a pan-tropical/subtropical distribution that attacks a wide range of tree hosts. For this study, genomic sequencing was conducted on P. noxius isolate P919-02W.7 from Federated States of Micronesia (Pohnpei), and its gene expression profile was analyzed using different host wood (Acer, Pinus, Prunus, a...

Phellinus noxius, the cause of brown root-rot disease, is an invasive fungal pathogen that causes a white rot among woody plants in Asia, Oceania, and Africa. Because the origin and diversity of this pathogen are unknown, it is difficult to predict its behavior and invasive capacity, especially under future climate-change scenarios. We characterize...

This poster summarizes a study that examined 2076 planted western whitepine trees in northern Idaho. 1) 54% were found to be colonized by Armillaria. 2) Trees colonized only by A. altimontana exhibited the highest growth and survival and low incidence of Armillaria root rot disease. 3) A. solidipes was uncommon in areas dominated by A. altimont...

Climate change is predicted to increase the impacts of Armillaria root disease as host trees become maladapted to their environment, escalating tree stress, and potentially increasing susceptibly to Armillaria pathogens (e.g., Klopfenstein et al. 2009, Kliejunas et al. 2009, Kliejunas 2011, Sturrock et al. 2011, Dempster 2017, Kubiak et al. 2017, A...

Research Highlights: Two genets of Armillaria altimontana Brazee, B. Ortiz, Banik, and D.L. Lindner and five genets of Armillaria solidipes Peck (as A. ostoyae [Romagnesi] Herink) were identified and spatially mapped within a 16-year-old western white pine (Pinus monticola Doug.) plantation, which demonstrated distinct spatial distribution and inte...

Disease caused by Armillaria mexicana and/or A. mellea is associated with tree mortality in peach (Prunus persica) orchards within their primary production zone of the Mexican sub-tropics. To improve management options for this disease, the resistance/susceptibility reactions of three Prunus rootstocks to infection by A. mexicana (isolate MEX85) an...

Raffaelea lauricola is an invasive fungal pathogen and symbiont of the redbay ambrosia beetle (Xyleborus glabratus) that has caused widespread mortality to redbay (Persea borbonia) and other Lauraceae species in the southeastern USA. We compare two genomes of R. lauricola (C2646 and RL570) to seven other related Ophiostomatales species including R....

Purpose of Review The continued, rapid development of novel molecular genetic tools is contributing to a better understanding of forest-associated fungi and their interactive roles within diverse forest ecosystems. This paper focuses on recent developments of DNA-based diagnostics/detection, phylogenetics, population genetics, genomics, and metagen...

Supplementary Table 1

Armillaria mexicana (Agaricales, Physalacriaceae) is described as a new species based on morphology, DNA-sequence data, and phylogenetic analyses. It clearly differs from previously reported Armillaria species in North, Central, and South America. It is characterized by the absence of fibulae in the basidioma, abundant cheilocystidia, and ellipsoid...

Since the myrtle rust pathogen (Austropuccinia psidii) was first reported (as Puccinia psidii) in Brazil on guava (Psidium guajava) in 1884, it has been found infecting diverse myrtaceous species. Because A. psidii has recently spread rapidly worldwide with an extensive host range, genetic and genotypic diversities were evaluated within and among A...

The fungus Raffaelea quercus-mongolicae is the causal agent of Korean oak wilt, a disease associated with mass mortality of oak trees (e.g., Quercus spp.). The fungus is vectored and dispersed by the ambrosia beetle, Platypus koryoensis . Here, we present the 27.0-Mb draft genome sequence of R. quercus-mongolicae strain KACC44405.

Eucalypt powdery mildew is an important disease in greenhouses and clonal hedges of Eucalyptus spp. in Brazil, which can cause leaf and shoot distortion, shoot discoloration, and growth reduction that results in production losses. Because reliable information regarding the causal agent of the disease is lacking, this study used ITS and 28S rDNA seq...

Koa (Acacia koa) and ‘ōhi‘a lehua (Metrosideros polymorpha) are the two most dominant native tree species in Hawai‘i. Their populations are continuously decreasing, primarily because of forest disease (Dudley et al. 2007;Keith et al. 2015) and other biotic disturbances. In April 2015, Armillaria rhizomorphs were collected from woody hosts on the is...

Fusarium species, specifically F. commune, F. proliferatum, and F. solani, can cause severe damping-off and root disease in container and bareroot forest nurseries throughout North America. Many conifer and hardwood species can be affected, but Douglas-fir (Pseudotsuga menziesii), western white pine (Pinus monticola), and ponderosa pine (P. pondero...

Raffaelea quercus-mongolicae is a fungus associated with oak wilt and deemed to cause extensive oak mortality in South Korea. Since the discovery of this fungus on a dead Mongolian oak (Quercus mongolica) in 2004, the mortality continued to spread southwards in South Korea. Despite continued expansion of the disease and associated significant impac...

This research evaluated the influence of different washing treatments (i.e., tap water, ozone, microbubbles, and ozone combined with microbubbles) on post-harvest decay of chestnuts (Castanea crenata ‘Tsukuba’) during storage. Overall, treatments with ozone and microbubbles significantly reduced the decay frequency and the associated microbial popu...

In July 2014, mycelial fans (isolates CO104F, CO106F, and CO108F) of Armillaria sp. were collected from forest trees in Colorado. These isolates were all identified as A. sinapina based on a somatic pairing test against 18 tester isolates representing six North American Armillaria spp. and nucleotide sequences of the translation elongation factor 1...