scholarly journals Detection of natural infection of Quercus spp. by the chestnut blight fungus (Cryphonectria parasitica) in Hungary

2002 ◽  
Vol 8 (2) ◽  
Author(s):  
L. Radócz ◽  
I. J. Holb
Keyword(s):  
Natural Infection ◽  
Cryphonectria Parasitica ◽  
Castanea Dentata ◽  
American Chestnut ◽  
Chestnut Blight ◽  
Chestnut Blight Fungus ◽  
European Chestnut ◽  
Total Destruction ◽  
Quercus Spp ◽  
Endothia Parasitica

The chestnut blight fungus Cryphonectria parasitica (Murrill) Barr [syn.: Endothia parasitica (Murr) Anderson] caused almost total destruction of the American chestnut (Castanea dentata) and widely spread on European chestnut (Castanea saliva) in many European countries. In Hungary, because this fungus threatens most of the Hungarian chestnut stands, great efforts have been made to delay its spread. Biological control with Hungarian hypovirulent strains of the pathogen seems to be an effective method for saving the affected chestnut trees. Until 1998 the fungus was detected on Castanea saliva only, then on some trees of young Quercus petrea in mixed chestnut forests, which also showed the typical symptoms of blight (Kőszeg and Zengővárkony). Although blight symptoms are not so serious in Quercus spp. than in Castanea spp., it seems that C. parasitica threatens the young Quercus spp. in Hungary, mainly in heavily infected chestnut forests. This is the first report of C. parasitica cankers on oak in Hungary.

Movement of cytoplasmic hypovirulence agents in chestnut blight cankers

1992 ◽  
Vol 70 (3) ◽  
pp. 557-561 ◽  
Author(s):  
L. Shain ◽  
J. B. Miller
Keyword(s):  
Biological Control ◽  
Key Words ◽  
Cryphonectria Parasitica ◽  
Castanea Dentata ◽  
American Chestnut ◽  
Chestnut Blight ◽  
Typical Morphology ◽  
Natural Range ◽  
Hypovirulent Strain ◽  
Endothia Parasitica

Chestnut blight cankers, initiated with virulent methionine auxotrophic strains of Cryphonectria parasitica, were challenged by placing one or two discs of agar and mycelium of prototrophic hypovirulent strains at their base. Movement of hypovirulence agents was confirmed by recovery of an isolate that exhibited the typical morphology of the introduced hypovirulent strain on media with methionine but little or no growth on media without methionine. Cultures from bark showed that the hypovirulent agent moved through mycelium around the circumference of cankers within 3 weeks when the virulent and challenging hypovirulent were vegetatively compatible. Conversion of the mycelium in the canker interior proceeded more slowly. Conversion of mycelium also was delayed, but eventually occurred, when virulent and hypovirulent inocula differed in vegetative compatibility. Conidia, however, continued to yield virulent, methionine-requiring cultures up to 65 weeks after challenge, even though underlying bark frequently yielded hypovirulent, methionine-requiring cultures. This disinclination of hypovirulent agents to enter the asexual apparatus in cankers may contribute substantially to the observed ineffective dissemination of hypovirulence in the natural range of American chestnut. Exploitation of those hypovirulent agents that can enter conidia in cankers may enhance the biological control of chestnut blight by hypovirulence. Key words: biological control, Cryphonectria parasitica, Endothia parasitica, Castanea dentata.

Dendroecology of American chestnut in a disjunct stand of oak–chestnut forest

2006 ◽  
Vol 36 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Ryan W McEwan ◽  
Carolyn H Keiffer ◽  
Brian C McCarthy
Keyword(s):  
Radial Growth ◽  
Light Availability ◽  
Cryphonectria Parasitica ◽  
Castanea Dentata ◽  
Growth Patterns ◽  
American Chestnut ◽  
Chestnut Blight ◽  
Chestnut Blight Fungus ◽  
Hardwood Species ◽  
Restoration Potential

American chestnut (Castanea dentata (Marsh.) Borkh.) was once an important hardwood species in the forests of eastern North America. Following the chestnut blight fungus (Cryphonectria parasitica (Murrill) Barr) pandemic of the early 20th century, C. dentata remains only as sprouts throughout much of its range. We conducted a dendroecological analysis of a large naturalized stand of mature C. dentata to evaluate the species' growth capacity, ecology, and restoration potential. Eestablishment of C. dentata was sporadic in the first 40 years of our chronology, followed by a disturbance-associated recruitment pulse. The species appears to be tolerant of suppression in the understory, but responded to release with rapid radial growth (>10 mm·year–1). Although its climate–growth relationships are similar to those of other hardwood species, mean radial growth of C. dentata was nearly twice that of other hardwood species found in the stand (4.7 ± 0.21 vs. 2.5 ± 0.16 mm·year–1). Chestnut blight has recently infected this stand, resulting in a sharp depression in the growth chronology of C. dentata, even when outward signs of infection were not yet visible. Observed establishment and growth patterns suggest that blight-resistant C. dentata is likely to attain dominance rapidly in forests where restoration efforts include canopy manipulations that increase light availability.

scholarly journals Hard Mast Production Before and After the Chestnut Blight

2000 ◽  
Vol 24 (4) ◽  
pp. 196-201 ◽  
Author(s):  
Seth J. Diamond ◽  
Robert H. Giles ◽  
Roy L. Kirkpatrick ◽  
Gary J. Griffin
Keyword(s):  
Carrying Capacity ◽  
Basal Area ◽  
Cryphonectria Parasitica ◽  
Castanea Dentata ◽  
Chestnut Blight ◽  
Wildlife Species ◽  
Chestnut Blight Fungus ◽  
Southern Appalachian ◽  
Before And After ◽  
Mast Production

Abstract We estimated hard mast production of a Southern Appalachian forest for two 10 yr intervals: one before and one, 35 yr after, the chestnut blight fungus (Cryphonectria parasitica) (Murr.) Barr, had killed all mature chestnut trees. The basal area of hard mast-producing trees in the postblight forest was 28% less than in the preblight forest. The estimate of hard mast output was 34% less after the chestnut blight. Postblight production was less than preblight production for 8 of 10 yr. During 5 of these years, postblight production was only 5-27% of preblight production. Annual preblight mast production was relatively stable, whereas annual postblight production fluctuated substantially. Our findings suggest that the loss of mature chestnuts (Castanea dentata) markedly reduced the Southern Appalachian forest's carrying capacity for certain wildlife species. South. J. Appl. For 24(4):196-201.

scholarly journals Resistance toPhytophthora cinnamomiin American Chestnut (Castanea dentata) Backcross Populations that Descended from Two Chinese Chestnut (Castanea mollissima) Sources of Resistance

Plant Disease ◽  
2019 ◽  
Vol 103 (7) ◽  
pp. 1631-1641 ◽  
Author(s):  
Jared W. Westbrook ◽  
Joseph B. James ◽  
Paul H. Sisco ◽  
John Frampton ◽  
Sunny Lucas ◽  
...  
Keyword(s):  
Phytophthora Cinnamomi ◽  
Seedling Survival ◽  
Cryphonectria Parasitica ◽  
Castanea Dentata ◽  
American Chestnut ◽  
Chestnut Blight ◽  
Sources Of Resistance ◽  
Backcross Population ◽  
Chinese Chestnut ◽  
Root Health

Restoration of American chestnut (Castanea dentata) depends on combining resistance to both the chestnut blight fungus (Cryphonectria parasitica) and Phytophthora cinnamomi, which causes Phytophthora root rot, in a diverse population of C. dentata. Over a 14-year period (2004 to 2017), survival and root health of American chestnut backcross seedlings after inoculation with P. cinnamomi were compared among 28 BC3, 66 BC4, and 389 BC3F3families that descended from two BC1trees (Clapper and Graves) with different Chinese chestnut grandparents. The 5% most resistant Graves BC3F3families survived P. cinnamomi infection at rates of 75 to 100% but had mean root health scores that were intermediate between resistant Chinese chestnut and susceptible American chestnut families. Within Graves BC3F3families, seedling survival was greater than survival of Graves BC3and BC4families and was not genetically correlated with chestnut blight canker severity. Only low to intermediate resistance to P. cinnamomi was detected among backcross descendants from the Clapper tree. Results suggest that major-effect resistance alleles were inherited by descendants from the Graves tree, that intercrossing backcross trees enhances progeny resistance to P. cinnamomi, and that alleles for resistance to P. cinnamomi and C. parasitica are not linked. To combine resistance to both C. parasitica and P. cinnamomi, a diverse Graves backcross population will be screened for resistance to P. cinnamomi, survivors bred with trees selected for resistance to C. parasitica, and progeny selected for resistance to both pathogens will be intercrossed.

Initiation and development of cankers caused by virulent and cytoplasmic hypovirulent isolates of the chestnut blight fungus

1984 ◽  
Vol 62 (12) ◽  
pp. 2660-2664 ◽  
Author(s):  
J. S. Russin ◽  
L. Shain
Keyword(s):  
Moisture Content ◽  
Electrical Resistance ◽  
American Chestnut ◽  
Chestnut Blight ◽  
Moisture Contents ◽  
Chestnut Blight Fungus ◽  
Cork Borer ◽  
Endothia Parasitica ◽  
Canker Development

Stems of American chestnut were inoculated with a virulent (V) isolate of Endothia parasitica alone or containing different agents for cytoplasmic hypovirulence (CH). The V isolate (EP 155) initiated cankers in cork borer wounds 0,1,2,4,7,14,21, or 28 days old. Infection of this V isolate with CH agents Hl2 (EP 780), HMU (EP 868) or HT2 (EP 905), restricted canker development to wounds 0–7 days old, Odays old, or to none of the wounds 0–28 days old, respectively. Inoculation of several wound types with V or CH conidia collected from cankers or agar cultures resulted in few cankers. Measurement of electrical resistance (ER) of bark at different heights along chestnut stems indicated that ER was lowest at stem bases. Cankers initiated artificially at stem bases with mycelium from V or CH isolates were smaller and enlarged more slowly than did cankers initiated at more elevated stem positions. Areas of cankers initiated in detached chestnut stems in which moisture contents were regulated were inversely related to moisture content and directly related to ER of chestnut bark.

scholarly journals Emergence and diversification of a highly invasive chestnut pathogen lineage across southeastern Europe

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Lea Stauber ◽  
Thomas Badet ◽  
Alice Feurtey ◽  
Simone Prospero ◽  
Daniel Croll
Keyword(s):  
Cryphonectria Parasitica ◽  
Chestnut Blight ◽  
Southeastern Europe ◽  
Chestnut Blight Fungus ◽  
The North ◽  
Fitness Advantage ◽  
European Chestnut ◽  
Recent Outbreak ◽  
Single Mating ◽  
European Genotype

Invasive microbial species constitute a major threat to biodiversity, agricultural production and human health. Invasions are often dominated by one or a small number of genotypes, yet the underlying factors driving invasions are poorly understood. The chestnut blight fungus Cryphonectria parasitica first decimated the North American chestnut, and a more recent outbreak threatens European chestnut stands. To unravel the chestnut blight invasion of southeastern Europe, we sequenced 230 genomes of predominantly European strains. Genotypes outside of the invasion zone showed high levels of diversity with evidence for frequent and ongoing recombination. The invasive lineage emerged from the highly diverse European genotype pool rather than a secondary introduction from Asia or North America. The expansion across southeastern Europe was mostly clonal and is dominated by a single mating type, suggesting a fitness advantage of asexual reproduction. Our findings show how an intermediary, highly diverse bridgehead population gave rise to an invasive, largely clonally expanding pathogen.

Population biology of the chestnut blight fungus, Cryphonectria parasitica

1995 ◽  
Vol 73 (S1) ◽  
pp. 311-319 ◽  
Author(s):  
Michael G. Milgroom
Keyword(s):  
Gene Flow ◽  
North America ◽  
Population Biology ◽  
Random Mating ◽  
Cryphonectria Parasitica ◽  
Vegetative Compatibility ◽  
Chestnut Blight ◽  
Vegetative Compatibility Groups ◽  
Chestnut Blight Fungus ◽  
Endothia Parasitica

Interest in the population biology of the chestnut blight fungus Cryphonectria parasitica has been motivated largely by the potential for biological control of chestnut blight with fungal viruses that cause hypovirulence. Earlier studies gave valuable insights into the correlation between diversity of vegetative compatibility groups and transmission of hypovirulence viruses. However, inferences about evolutionary processes affecting populations were not possible because vegetative compatibility groups are not genetically defined. Using restriction fragment length polymorphism markers, however, progress has been made in studying the origin of C. parasitica in North America, gene flow among populations, dispersal within populations, and recombination and the mating system. Cryphonectria parasitica populations in North America are genetically more similar to populations in Japan than in China, which is consistent with previous speculations that this fungus was introduced from Japan. Populations in China and Japan are quite different, suggesting little or no gene flow between these areas. Restricted gene flow and genetic drift are probably the dominant evolutionary forces shaping North American populations, with approximately 20% of gene diversity due to differences among populations (GST = 0.20). Two populations of C. parasitica in Michigan and one population in Italy are primarily clonal in structure. In contrast, sexual reproduction appears to be common in populations in eastern North America, although most of these populations deviate significantly from random mating. Deviations from random mating are most likely due to self-fertilization (uniparental inbreeding), restricted dispersal of male gametes, and mating between individuals that are more closely related genetically than would be expected by chance (biparental inbreeding). Aggregations of similar genotypes in space suggest that populations of C. parasitica may be structured into genetic neighborhoods by restricted dispersal. Future research efforts in this system will explore isolation by distance and address questions of hypovirulence virus coevolution with its fungal host. Key words: Cryphonectria parasitica, Endothia parasitica, chestnut blight, genetic neighbourhoods, inbreeding.

scholarly journals 75 years of the chestnut blight fungus Cryphonectria parasitica (Murr.) Barr in Europe

2014 ◽  
pp. 82-85
Author(s):  
László Radócz ◽  
Gábor Görcsös ◽  
Gábor Tarcali ◽  
Gabriella Kovács ◽  
Qin Ling
Keyword(s):  
Biological Control ◽  
Cryphonectria Parasitica ◽  
Vegetative Compatibility ◽  
Chestnut Blight ◽  
Chestnut Blight Fungus ◽  
European Chestnut ◽  
High Prevalence ◽  
History Of ◽  
Short Time ◽  
High Diversity

The chestnut blight fungus Cryphonectria parasitica is a native pathogen in East Asia and has been introduced into North America and Europe. Historical records and population genetic studies revealed at least three major introduction events from Asia into Europe. Nowadays, chestnut blight is present in almost the entire distribution range of European chestnut, i.e. from the Iberian Peninsula to the Caucasus. The C. parasitica population in most countries has been studied in respect to the diversity of vegetative compatibility (vc) types and the occurrence of hypovirulence. The vc type diversity of the different populations varied considerably. Typically, a high diversity of vc types has been found in areas with a long history of chestnut blight and where sexual recombination between divergent genotypes commonly has occurred. On the other hand, newly established populations often showed a low diversity with only one, or a few vc types present. Hypovirulence, i.e. the occurrence of C. parasitica isolates infected by Cryphonectria hypovirus 1 has been found widespread in Europe. Natural dissemination and active biological control applications have lead to a high prevalence of the hypovirus and to the recovery of many chestnut stands. Virulent cankers became hypovirus-infected within a short time and ceased expansion. There is concern that the diversity of vegetative compatibility types could increase in Europe through sexual reproduction between C. parasitica genotypes originating from different introductions. A higher level of vegetative incompatibility would not only hamper hypovirus spread within a population but could also select for lower virulence in CHV-1 and subsequently lead to an erosion of biological control. Recent studies, however, indicate that the vc type barriers are not so restrictive than previously assumed and that so far no evidence for an erosion of biological control system in high diversity populations can be observed.

Birds and mammals as vectors of the chestnut blight fungus (Endothia parasitica)

1981 ◽  
Vol 59 (9) ◽  
pp. 1647-1650 ◽  
Author(s):  
Craig S. Scharf ◽  
Nancy K. DePalma
Keyword(s):  
Hardwood Forests ◽  
American Chestnut ◽  
Forest Community ◽  
Chestnut Blight ◽  
Chestnut Blight Fungus ◽  
Endothia Parasitica

This study investigated the potential of birds and mammals to vector the chestnut blight fungus in today's mixed hardwood forests. Animals were shot or trapped in established woodland plots in southern Connecticut where densities of American chestnut sprouts were high, brought back to the laboratory, and examined for the presence of Endothia parasitica. Results showed that birds and mammals can transport virulent and hypovirulent-like strains of E. parasitica in today's forest community. Two birds, a mouse, and a shrew were identified as carriers of the blight fungus; the shrew harbored a hypovirulent-like strain introduced onto the plot 2 years earlier.

Spatial pattern analysis of vegetative compatibility groups in the chestnut blight fungus, Cryphonectria parasitica

1991 ◽  
Vol 69 (7) ◽  
pp. 1407-1413 ◽  
Author(s):  
Michael G. Milgroom ◽  
William L. MacDonald ◽  
Mark L. Double
Keyword(s):  
Average Distance ◽  
Cryphonectria Parasitica ◽  
Mantel Test ◽  
Vegetative Compatibility ◽  
Chestnut Blight ◽  
Spatial Pattern Analysis ◽  
Vegetative Compatibility Groups ◽  
Clear Cut ◽  
Chestnut Blight Fungus ◽  
Endothia Parasitica

Vegetative compatibility groups were determined for 914 isolates of the chestnut blight fungus, Cryphonectria (Endothia) parasitica, collected over a 5-year period from American chestnut trees in eight regenerating clear-cut plots. We tested the hypothesis that the average distance between individuals in the same vegetative compatibility group is not different from the average distance between individuals with vegetative compatibility assigned at random. Nonrandom patterns were detected in all plots at least once during the study, indicating that vegetative compatibility groups were often aggregated. However, when multiple occurrences of vegetative compatibility groups on the same tree were eliminated from the analysis, there was only one test (out of 98 in total) in which the null hypothesis was rejected. We conclude that nonrandom patterns of vegetative compatibility groups are due primarily to multiple occurrences of vegetative compatibility groups on the same trees. Nearly half of all new cankers detected once the epidemic got started were in the same vegetative compatibility groups as cankers previously resident on the same tree. These data are consistent with the hypothesis that populations of C. parasitica are partly clonal in structure. Key words: Endothia parasitica, hypovirulence, Mantel test, matrix comparison, spatial autocorrelation.

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