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1.
Armillaria spp. are some of the most important forest pathogens in mixed hardwood forests of southern New England, yet their role as prominent disturbance agents is still not fully appreciated. We investigated the distribution of Armillaria species across eight separate stands of northern hardwood and mixed oak forests in western Massachusetts. We were specifically interested in the Armillaria species distribution from live, symptomatic hosts and not in determining overall incidence in the forest. From 32 plots (16 within each forest type), 320 isolates were collected. Armillaria was routinely encountered causing disease of live trees. In total, 89% (286/320) of all isolations came from live hosts exhibiting symptoms of root and butt rot. Overall, A. gallica was the dominant species in each forest type, making up 88/160 (55%) isolates from northern hardwood and 153/160 (96%) of all isolations from mixed oak stands. However, northern hardwood forests showed much greater species diversity, as A. calvescens, A. gemina, A. ostoyae, and A. sinapina were all found. At one site, a northern hardwood forest surrounding a high elevation spruce-fir forest, A. ostoyae was the most abundant species encountered. All five Armillaria species were found causing disease of live hosts, including A. gemina, a species considered by some as weakly virulent. Armillaria gallica was found on 22/23 tree species’ sampled, and was found most often causing butt rot. 相似文献
2.
The occurence of Armillaria species was assessed in Norway, enabling the northern‐most distribution of this genus to be determined in Europe. Four Armillaria species were found in Norway. Armillaria borealis was the most common species occurring on woody vegetation to the permafrost zone (ca. 69°N). Armillaria cepistipes was present in southern and central Norway, but was not found further than 66°N. Armillaria solidipes and Armillaria gallica were rare, found at only one locality each; 59°40′ and 59°32′, respectively. Armillaria species were found on 14 hosts, but there was no significant difference between occurrence of A. borealis and A. cepistipes on declining and dead trees. Phylogenetic analyses separated each species into separate clades. All isolates of A. borealis, except one, and most isolates of A. solidipes were in separate clades. However, a subclade within the A. borealis clade was formed of two A. ostoyae and one A. borealis isolates. Two small A. cepistipes genets were found in a declining oak stand. 相似文献
3.
J. N. Bruhn J. J. Wetteroff J. D. Mihail J. M. Kabrick J. B. Pickens 《Forest Pathology》2000,30(1):43-60
Armillaria root disease is a contributing factor to oak decline in the Ozark Mountains of central USA. We have identified Armillaria gallica, Armillaria mellea, and Armillaria tabescens in Quercus‐Carya‐Pinus forests of the region. Presence/absence patterns of each Armillaria species as well as all possible Armillaria species combinations were analysed by contingency tables and/or stepwise logistic multiple regressions with principal characteristics of the studied sites and forest stands, both quantitative and qualitative: geographic land‐type association, bedrock type, landform position, slope direction (aspect), soil type and soil surface stone cover, down woody debris, abundance and basal area of woody vegetation and decline mortality by species. Most decline mortality consisted of two red oak species (section Erythrobalanus, Quercus coccinea and Quercus velutina), which also were most sensitive to Armillaria infection. Site characteristics related to the distributions of Armillaria species and decline mortality were also related to the preponderance of Q. coccinea and Q. velutina, regional vegetation history (i.e. conversion of Pinus echinata stands to hardwoods), and the different strategies of territory acquisition and spread of the Armillaria species involved. The presence of A. gallica may reduce the activity of more virulent Armillaria species. 相似文献
4.
The distribution of Armillaria species was investigated in Serbian forest ecosystems, in relation to the main host species attacked, forest‐types, geography and altitude. In total, 388 isolates were identified from 36 host species in 47 sites. Armillaria gallica was the most commonly observed species with the widest distribution and with an altitudinal range of 70–1450 m, it was the dominating Armillaria species in lowland alluvial forests and in Quercus and Fagus forests at higher elevations. Armillaria mellea occurred in Quercus spp. – dominated forests in the north and central regions at 70–1050 m. Sixty‐eight per cent of the A. mellea isolates were collected from living hosts, most commonly in declining conifer plantations. Armillaria ostoyae was distributed in the cooler coniferous forest types and plantations in the Dinaric Alps in the south of Serbia, at 850–1820 m. Armillaria cepistipes was found in the eastern and southern hilly and mountainous regions of the country, at 600–1900 m. Most isolates were obtained from conifers and rhizomorphs in the soil around decaying stumps. Armillaria tabescens was found only on dead oak material in the northern and eastern regions of the country at altitudes lower than 600 m. 相似文献
5.
P. Tsopelas 《Forest Pathology》1999,29(2):103-116
Five Armillaria species were identified in a nationwide survey in Greece. Armillaria mellea was present in coniferous and broad-leaved forests in most of the areas examined, except the high altitudes (above 1100 m) of the mountains of north Greece. It was found to cause significant damage in fir forests as well as in fruit orchards and vineyards. Armillaria gallica was common in coniferous and broad-leaved forests in the high altitudes of central and northern Greece, predominating in the beech forests. The fungus was a weak parasite or a saprophyte of forest trees and was occasionally found on cultivated plants. Armillaria ostoyae was not found in southern and central parts of the country, but it has a wide distribution in the mountain forests of northern Greece and causes significant damage on fir, black pine, Scots pine and spruce. Armillaria cepistipes was recorded at high altitudes (1400–1800 m) on two mountains of northern Greece, mostly as a saprophyte in coniferous and broad-leaved forests. Armillaria tabescens was rare in the forests of Greece; it was found to cause disease in almond tree orchards. 相似文献
6.
Brandon C. Alveshere Shawn McMurtrey Patrick Bennett Mee‐Sook Kim John W. Hanna Ned B. Klopfenstein James T. Blodgett Jared M. LeBoldus 《Forest Pathology》2021,51(1):e12663
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 Armillaria spp. taxonomic diversity. Genetic sequencing has facilitated the mapping of species distributions and host associations, providing insights into Armillaria ecology. These studies can help to inform forest management and are essential in the development of disease risk maps, leading to more effective management strategies for Armillaria root disease. Armillaria surveys were conducted on publicly owned lands in North Dakota, South Dakota, and Nebraska, U.S.A. Surveyed stands consisted of riparian forests ≥0.4 hectares in area. Armillaria was found at 78 of 101 sites. A total of 57 Armillaria isolates—associated with 12 host tree species—were used for DNA sequencing of the translation elongation factor‐1 alpha (tef1) gene. Armillaria gallica was the only species identified within the study sites. Results suggest that A. gallica is a common root pathogen of hardwood trees in riparian forests of the northern Great Plains with a wider host range and geographic distribution than previously recognized. 相似文献
7.
8.
Forests in the Ozark Mountains of northern Arkansas recently experienced a widespread oak decline event. Armillaria, a root rot fungus, has been associated with other oak decline events and may have been an important contributing factor to tree mortality in this event. Although Armillaria has been identified from the Ozark Mountains in Missouri, it has never been investigated in the Arkansas Ozarks. Molecular diagnostic techniques were used in this study to identify species of Armillaria present on roots removed from dead trees of two common oak species, northern red oak, Quercus rubra L., and white oak, Q. alba L., from three geographic areas and on three topographic positions – ridges, south‐ and west‐facing benches. Armillaria(A. mellea, A. gallica or A. tabescens) was identified from 31% of root samples taken from 102 trees in seven of nine sample plots. Armillaria mellea, occurred most often (20 samples, both oak species on seven plots) followed by A. gallica (10 samples, northern red oak only on four plots), and A. tabescens occurred twice (on northern red oak in a single plot). Thus, all three Armillaria species occurred on northern red oaks while A. mellea was the only species recovered from white oaks. Results varied by topographic position with samples from tree roots on ridges having the fewest positive identifications, one of 29. West‐facing benches had the highest positive samples with 20 of 41 testing positive and trees on south‐facing benches were intermediate with 11 of 32 samples from infected trees. This study documents the occurrence of three species of Armillaria in the Arkansas Ozarks and their association with oak mortality resulting from an oak decline event coupled with a red oak borer, Enaphalodes rufulus, outbreak. Further, it documents some potential variation in host/pathogen combinations and forest site conditions. 相似文献
9.
A study was conducted in coastal Andhra Pradesh to evaluate current practices and suitability of coastal sandy soils for raising tree plantations. Poor soil moisture retention characteristics of these soils make irrigation an essential, but costly silvicultural practice for obtaining desirable establishment and growth. Saline ground water is the only available source of irrigation. Its use seems safe and successful in such soils. The farmers have adopted a specialized manual splashing technique (Doruvu) of seepage pits for irrigating tree plantations in their establishment phase. This technique was observed to be well suited to the sandy soils. Casuarina equisetifolia and Eucalyptus tereticornis were the two most popular species being afforested. E. camaldulensis is also in an introduction phase. Comparison of growth performance and biomass accumulation by C. equisetifolia and E. tereticornis plantations at different growth stages showed the former to be significantly better than the latter. Build up of the soil organic carbon was also found to be markedly more in comparable C. equisetifolia plantations than those of E. tereticornis. Similarly, the blanketing influence of C. equisetifolia plantations was observed to modify soil temperature extremes considerably more than in the case of E. tereticornis. The findings, indicated a vast scope for utilization of coastal sandy soils for afforestation with the successful use of saline ground waters. 相似文献
10.
Armillaria ostoyae, Perenniporia subacida, Resinicium bicolor and Scytinostroma galactinum, root and butt rot fungi found on red spruce, Picea rubens, were tested, in vitro, for their sensitivity to metals typically found in high elevation forest soils where red spruce grows. Rhizomorph production by A. ostoyae from woody inocula in soils from red spruce stands at three elevations at each of five mountainous sites in the eastern United States was inhibited completely in the mineral soil from all elevations at all sites, and was also reduced significantly in the organic horizon from the upper two elevations at three of the sites. Inhibition was correlated with concentrations of metal ions in the soil. Growth of rhizomorphs into an agar medium containing lead and other heavy metals was inhibited for isolates of A. ostoyae from red spruce, but not for an isolate of Armillaria gallica from sugar maple; aluminium inhibited rhizomorph growth of isolates of both species. Mycelial growth of all four root and butt rot fungi was inhibited by lead, aluminium and other heavy metals depending on the solubility and concentration of metal and pH of the medium; growth inhibition was usually greater at an initial pH of 3.5 than at pH 4.5. Metal ions inhibited radial growth of Armillaria species more than that of the other three fungi. Rhizomorph growth of Armillaria was inhibited more than radial growth. Because local spread of A. ostoyae occurs frequently by means of rhizomorph growth between near roots, increases in lead, aluminium and other metals in the forest floor may contribute to this fungus' scarcity in high elevation soils and reduced incidence of infection at these sites in the eastern United States. 相似文献
11.
Trap bags were used to assess the presence of anArmillaria species in aPinus koraiensis plantation in Heilongjiang, China. 216 trap bags containing bark were placed in three plots at 2 × 2m spacing. After 10 weeks,
the presence ofArmillaria was determined from the growth of rhizomorphs in the trap bags. The trap bag method proved successful in determining the
presence of viableArmillaria rhizomorphs where only a few dead trees showed signs of the disease. The distribution of positive traps corresponded generally
with the presence of rhizomorphs in the soil taken from the trap holes. However, the trap bags were superior to soil samples
for evaluating the presence of viable rhizomorphs. The fresh, abundant rhizomorphs were easily identified by persons inexperienced
in the assessmentof Armillaria root rot. Several practical problems need to be solved before the method is applicable in general forest management in China. 相似文献
12.
Armillaria causes problems of root rot, kill trees and decay wood in the forests of Serbia and Montenegro, but the species involved have not hitherto been identified. The aim of this study was to identify field isolates collected on 25 localities. Identification was based on restriction fragment length polymorphism (RFLP) analysis of intergenic spacer 1 (IGS1) region and comparisons of IGS1 sequence with those available on NCBI database. Phylogenetic analysis was performed on sequence information from selected isolates to determine possible interrelationships between isolates with different banding patterns and previously identified tester isolates of five European Armillaria species. Five Armillaria species were identified in 90 isolates obtained from forests in Serbia and Montenegro. Armillaria gallica was most frequently isolated, followed by A. cepistipes, A. mellea, A. ostoyae and A. tabescens; two isolates remained unidentified. Restriction digestion of IGS1 amplification products with AluI produced 10 RFLP patterns. Patterns G4 (400, 250, 180) for A. gallica and pattern X (400, 180, 140) for isolates 74 and 79 are reported for the first time in European isolates. Eight RFLP patterns were observed after restriction with TaqI. Two patterns each were observed for A. ostoyae and A. gallica, and one each for A. cepistipes, A. mellea, A. tabescens and isolates 74 and 79. Parsimony analyses based on the IGS1 region placed the isolates into four clades: one including A. mellea, the second containing A. gallica–A. cepistipes isolates, while isolates of A. ostoyae and A. borealis were in the third clade. Armillaria tabescens differed from all annulate species. Phylogenetic analysis supported the conclusion that European Armillaria species are closely related and separated from a common ancestor in the near past. According to this survey five European Armillaria species are present in the forests of Serbia and Montenegro, while A. borealis is not present in the studied ecosystems. 相似文献
13.
The use of entomopathogenic nematodes is one potential non-chemical approach to control the larvae of the invasive western
corn rootworm (Diabrotica virgifera virgifera LeConte, Coleoptera: Chrysomelidae) in Europe. This study investigated the efficacy of Heterorhabditis bacteriophora Poinar (Rhabditida: Heterorhabditidae), Heterorhabditis megidis Poinar, Jackson and Klein (Rh., Heterorhabditidae) and Steinernema feltiae Filipjev (Rh., Steinernematidae) in reducing D. v. virgifera as a function of soil characteristics. A field experiment was repeated four times in southern Hungary using artificially
infested maize plants potted into three different soils. Sleeve gauze cages were used to assess the number of emerging adult
D. v. virgifera from the treatments and untreated controls. Results indicate that nematodes have the potential to reduce D. v. virgifera larvae in most soils; however, their efficacy can be higher in maize fields with heavy clay or silty clay soils than in sandy
soils, which is in contrast to the common assumption that nematodes perform better in sandy soils than in heavy soils. 相似文献
14.
V. Mulholland G. A. MacAskill B. E. Laue H. Steele D. Kenyon S. Green 《Forest Pathology》2012,42(3):229-238
The overall aim of this study was to develop a new, reliable and rapid diagnostic assay for differentiating six European Armillaria species based on variation in their elongation factor‐1 alpha (EF‐1 α) gene sequences and to verify a set of species‐specific primers on 61 Armillaria isolates from Europe. Partial sequences of the EF‐1 α gene obtained in Armillaria borealis, Armillaria cepistipes, Armillaria gallica, Armillaria mellea, Armillaria ostoyae and Armillaria tabescens revealed sufficient interspecific variation to distinguish among species using nested primers. These primers gave unambiguous bands when tested on representative isolates of five of these species. However, the EF‐1 α sequences of European A. borealis isolates clustered into two distinct clades, termed here AbX and AbY. Specific primers were subsequently designed and tested successfully on both AbX‐type and AbY‐type A. borealis isolates. The taxonomy of A. borealis needs to be elucidated to determine whether a new, as yet unnamed Armillaria taxon exists in Europe. Three A. borealis isolates were also found to have heterozygous sites in their EF‐1 α sequences, which suggests that the gene could exist in more than one copy or that these isolates contain hybrid sequences. A pyrosequencing method was also developed, targeting a small region of EF‐1 α intron 4, which was able to differentiate European Armillaria isolates to the species level and additionally could distinguish AbX‐type and AbY‐type A. borealis isolates. 相似文献
15.
G. A. Kile 《Forest Pathology》1980,10(5):278-296
An undescribed but native species of Armillaria is a secondary pathogen in declining stands of Eucalyptus obliqua and Eucalyptus regnans in southern Tasmania. The fungus is almost ubiquitous in healthy and diseased forest and occurred epiphytically or parasitically in local lesions on the roots of 74 % of eucalypts partially excavated in 15 forest stands, 25–75 years of age. The fungus infected 85 % of logging stumps and 64 % of fire killed trees. Although the fungus only infected the sapwood of the eucalypts, it survived in infected stumps for at least 70 years. Rhizomorphs initiated most infections but did not grow freely through the soil. Pathogenicity tests confirmed that the Armillaria is a weak pathogen. 相似文献
16.
Identification of European Armillaria species using ribosomal DNA (rDNA) restriction-fragment-length polymorphisms (RFLPs) was studied. A total of 44 Armillaria isolates representing five European biological species were examined. Whole-cell DNAs were digested with one or two (double digest) restriction endonucleases and probed with a cloned plasmid carrying one complete rDNA repeat copy of Saccharomyces carlsbergensis. Applying the restriction endonuclease Bgl II in combination with either Eco RI, Bam Hl or Hin dIII, it was possible to detect rDNA RFLPs allowing differentiation between all five European Armillaria species investigated in the study. The most conclusive results were obtained in the rDNA/Ava II RFLP pattern. All biological species showed unique Ava II banding patterns. Generally speaking, the interspecific similarities were around 42% and lower, indicating a distinct species separation. The analysis of rDNA RFLP patterns by a restriction-enzyme-rDNA-probe combination (for instance, Ava II or Bgl II/Hin dIII; probe pMY 60) is a practical means of identifying European Armillaria species for further taxonomic, phylogenetic and host-pathogen interaction studies. 相似文献
17.
Armillaria species from Japan were characterized using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) of the intergenic spacer region-1 (IGS-1) of ribosomal DNA (rDNA). Eleven different digestion patterns by restriction endonuclease Alu I were found among 70 isolates of seven Armillaria species in Japan. Isolates within Armillaria nabsnona, A. ostoyae, A. cepistipes, and Japanese biological species E showed the same Alu I digestion patterns. Five Alu I patterns were detected for A. gallica, three patterns for A. mellea, and two patterns for A. tabescens. Seven Armillaria species in Japan were clearly distinguished by using the profiles obtained when PCR products were digested with Alu I, Msp I, and Hae III restriction enzymes. There was considerable variability of Alu I restriction sites within the IGS-1 between the isolates of five Armillaria species, A. gallica, A. nabsnona, A. cepistipes, A. mellea, and A. tabescens, in Japan and those of their European and North American counterparts. 相似文献
18.
Isabel A. Munck Denise R. Smith Theodore Sickley Glen R. Stanosz 《Forest Ecology and Management》2009
The shoot blight and canker pathogens Diplodia pinea and D. scrobiculata sporulate abundantly on cones of many pine hosts. Variation in incidence and abundance of potential inoculum from cones and frequency of asymptomatic persistence on or in shoots was examined for mature red pines in sites differing in dominant presettlement vegetation and soil type in Bayfield and Douglas counties in northern Wisconsin. Collections were made in each county from 6 plantations, 3 each in areas historically vegetated with jack pine and soils mapped as sands and three in areas historically vegetated with red pine with soils mapped as loamy sands. At each site, 5 cones were collected from each of 5 red pines and 10 shoots were collected from up to 5 red pines. Conidia from cones were quantified with a water wash and filtration technique. Diplodia species were cultured from surface-disinfested asymptomatic shoots. A species-specific PCR assay was used to identify the Diplodia species from cones and shoots. Although cones and asymptomatic shoots from each county yielded D. pinea and D. scrobiculata, D. pinea was detected more frequently. More conidia were obtained from cones from Douglas Co., where there is a history of severe shoot blight damage, than cones from Bayfield Co. In Douglas Co., more conidia were obtained from cones from plantations in areas of more sandy soil and presettlement jack pine dominance than cones from plantations in areas of less sandy soil and presettlement red pine dominance. The numbers of conidia and frequencies of cultural detection of Diplodia species from asymptomatic shoots at a site were positively correlated. These results provide evidence for site-related influences on abundance of pathogen inoculum and asymptomatic persistence on or in red pine crowns that may contribute to differences in frequency and severity of damage from Diplodia shoot blight. 相似文献
19.
Ken'ichirou Kosugi 《Journal of Forest Research》1997,2(1):1-8
The soil water retention model proposed by Kosugi was modified to have a relatively simple functional form. The resulting
water retention model (the lognormal distribution model) contains two parameters which have physical significance on the water
retention curve and are related directly to the statistics of the soil pore radius distribution functiong(r). The observed retention data sets of 282 undisturbed forest soils taken from Mashimo were analyzed using the lognormal distribution
model, and it was shown that the model performs fairly well for every data set. The estimated parameters of the model indicated
that the water retention characteristics of the undisturbed forest soils are related to the soil structure more closely than
to the soil texture. Many crumb-structure forest soils have greater median ofg(r) than the crumb and granular-structure soils. Disturbed loamy soils have smaller median ofg(r) than many of the undisturbed forest soils and disturbed sandy soils have smallerg(r) width than the forest soils. The brown forest soils taken from A-horizon generally have the greater median ofg(r) than the brown forest soils taken from B-horizon. Some of the brown forest soils have the greater width ofg(r) than the black soils. The median ofg(r) of brown forest soil taken from A-horizon generally becomes greater as the soil moisture condition becomes wet. 相似文献
20.
R. D. Elías‐Román R. A. Guzmán‐Plazola N. B. Klopfenstein D. Alvarado‐Rosales G. Calderón‐Zavala J. A. Mora‐Aguilera M.‐S. Kim R. García‐Espinosa 《Forest Pathology》2013,43(5):390-401
Incidence of peach [Prunus persica (L.) Batsch] tree mortality attributed to Armillaria root disease was assessed from 2009 to 2011 in 15 orchards in the State of Mexico, Mexico. Incidence increased gradually every year of assessment, reaching average values of 9.7, 15.3 and 20.3% tree mortality and 23.2, 24.7 and 28.3% disease‐impacted area of the orchards during 2009, 2010 and 2011, respectively. The cultivars ‘Nemaguard’ and ‘Criollo of La Goleta’, a local rootstock used in the region, were both susceptible to the disease. To identify species of Armillaria isolated from infected peach trees, two nuclear rDNA regions (partial 5.8S‐ITS2‐LSU D‐domains and partial 3′ LSU‐IGS1) and the translation elongation factor‐1α (tef‐1α) gene were sequenced and compared with sequences of known Armillaria species. DNA sequence analysis from 49 Armillaria isolates revealed that five isolates (10.2%) were Armillaria mellea and eight isolates (16.3%) were Armillaria gallica. DNA sequences from the remaining 36 isolates (73.5%) showed no close similarity to Armillaria sequences in GenBank, and apparently represent an undescribed Armillaria species. This undescribed species was the most widely distributed in the region of study. Separate phylogenetic analyses of the LSU region (D1–D3 domains concatenated with the partial 3′ end) and the tef‐1α region show that the undescribed species is quite distinct from other Armillaria spp. reported in North America. 相似文献