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.

scholarly journals The Morphology and the Biological Control of Cryphonectria parasitica

2012 ◽  
Vol 69 (1) ◽  
Author(s):  
Carmen Emilia PUIA ◽  
Daniela Andreea GRIGORESCU ◽  
Raluca Vasilica MICLEA
Keyword(s):  
Biological Control ◽  
Virulent Strain ◽  
Morphological Characteristics ◽  
Castanea Sativa ◽  
Cryphonectria Parasitica ◽  
Chestnut Blight ◽  
Dual Culture ◽  
Natural Form ◽  
Hypovirulent Strain ◽  
Endothia Parasitica

Cryphonectria parasitica  (Murr.) Bar [syn. Endothia parasitica (Murr. And.] (anamorf: Endothiella sp .) is the causal agent of chestnut bark disease or chestnut blight, disease which produced great damages throughout the world, for example, in Europe, the European chestnut tree ( Castanea sativa (P.) Mill) was heavily affected. Environmental concerns have focused attention on natural forms of disease control as an effective alternative to chemical pesticides. In the chestnut blight fungus, Cryphonectria parasitica deals with a natural form of biological control in which the virulence of a fungal pathogen is attenuated by an endogenous viral RNA genetic element- the hypovirulent strain. In our researches we picked samples of chestnut bark from different areas in Maramures county. We’ve isolated the fungus on PDA medium and we’ve studied the morphological characteristics of the usual virulent strain and we looked for a possible hypovirulent strain in order to study its capacity for biological control. The fungus develops in the bark and in cambium where forms a yellowish or brownish stroma and produces both conidia and ascospores. The pycnidia stromata break through the lenticels producing conidia and later in the same stroma develop the perithecia which produce ascospores. Both strains of the fungus were found in the research area. The hypovirulent strain had a slower development, showed no sporu lation and pigmentation “white cultural strain” and was tested in vitro for the capacity to convert the virulent isolates by dual culture tests.

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.

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.

scholarly journals 065 Genetic Diversity of the Allegheny Chinkapin (Castanea pumila var. pumila)

HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 452C-452
Author(s):  
Fenny Dane
Keyword(s):  
Genetic Diversity ◽  
Rapd Marker ◽  
Cryphonectria Parasitica ◽  
American Chestnut ◽  
Disease Spread ◽  
Conservation Strategies ◽  
Chestnut Blight ◽  
Geographic Populations ◽  
Natural Range ◽  
Conservation Plan

American species in the genus Castanea are susceptible to chestnut blight, caused by the Asian fungus Cryphonectria parasitica. This disease spread throughout the natural range of the American chestnut and reduced the species from a timber and nut producing tree to an understory shrub. The lesser known member of the genus, the chinkapin, has also been affected by this disease and a conservation plan is needed. Genetic diversity within and between geographic populations of the Allegheny chinkapin was evaluated to provide baseline genetic information pertinent to conservation of the species. Nuts of Allegheny chinkapin trees from populations in Mississippi, Florida, Alabama, Virginia, and Ohio were collected and evaluated for isozyme and RAPD marker polymorphism. The genetic diversity of these populations will be compared with that of Ozark chinkapin and American chestnut populations. Conservation strategies will be discussed.

Genetic Diversity of Castanea pulia var. ozarkensis

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 526e-527
Author(s):  
Fenny Dane ◽  
Shona Harrison ◽  
Hongwen Huang
Keyword(s):  
Genetic Diversity ◽  
Cryphonectria Parasitica ◽  
American Chestnut ◽  
Chestnut Blight ◽  
Ozark Highlands ◽  
The Past ◽  
Geographic Populations ◽  
Natural Range ◽  
Rapd Polymorphism ◽  
Taxonomic Studies

The genus Castanea includes several species, some of which, like the American chestnut (C. dentata) and chinkapin (C. pumila), are susceptible to chestnut blight, caused by the Asian fungus Cryphonectria parasitica. Blight spread throughout the natural range of the American chestnut, destroying several billion trees within the past 50 years. Although the plight of the American chestnut is well-known, the chinkapin has been neglected. Taxonomic studies indicated two varieties, the Ozark chinkapin, var. ozarkensis, limited to the Ozark Highlands of Arkansas, Missouri, and Oklahoma, and the Allegheny chinkapin, var. pumila, found from New Jersey to Florida and Texas. The genetic diversity within and between 11 geographic populations of the Ozark chinkapin was evaluated to provide baseline genetic information pertinent to the conservation and restoration of this species. Nuts or dormant buds of chinkapin trees were evaluated for isozyme and RAPD polymorphism. The genetic variability of the Ozark chinkapin populations was relatively high when compared to the American chestnut, and most of the diversity resides within the populations. Conservation considerations for restoration of the Ozark chinkapin will be discussed.

scholarly journals Biological control of sweet chestnut on Pécsbánya, Hungary

2018 ◽  
pp. 77-81
Author(s):  
Gabriella Kovács ◽  
Dominika Bodnár ◽  
Gábor Tarcali ◽  
László Radócz
Keyword(s):  
Biological Control ◽  
Biological Process ◽  
Cryphonectria Parasitica ◽  
Plant Health ◽  
Chestnut Blight ◽  
Gall Wasp ◽  
Sweet Chestnut ◽  
Dryocosmus Kuriphilus ◽  
Hypovirulent Strain ◽  
Blight Disease

The supervision of plant hygiene of sweet chestnut grove on Pécsbánya (South Hungary) started more than four years ago. Hypovirulent strains were applied as a biological process to control Cryphonectria parasitica fungus which causes the chestnut blight disease. By now the performed interventions have shown obvious results, the vitality of the trees has greatly improved, the amount of harvested nuts is increasing, and the hypovirulent strain has been spreading within the area. During plant health inspection the galls of chestnut gall wasp (Dryocosmus kuriphilus) was found in the year of 2015, which is the obvious symptom of new occurrence of the pest. The pest was eradicated by destroy galls, which allows taking out of consideration the damage by now in this area.

Cryphonectria parasitica. [Descriptions of Fungi and Bacteria].

1981 ◽  
Author(s):  
A. Sivanesan
Keyword(s):  
Geographical Distribution ◽  
Uttar Pradesh ◽  
Cryphonectria Parasitica ◽  
Castanea Dentata ◽  
American Chestnut ◽  
Chestnut Blight ◽  
Carya Ovata ◽  
Shagbark Hickory ◽  
British Colombia ◽  
Rhus Typhina

Abstract A description is provided for Cryphonectria parasitica. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Particularly Castanea dentata (American chestnut); other Castanea spp., Acer spp. Quercus spp., Carya ovata (shagbark hickory) and Rhus typhina (staghorn sumach), (30, 550; 33, 569; 34, 759; 42, 709; 43, 2426; 48, 946; 54, 1012; 56, 410; 57, 1569). DISEASE: Chestnut Blight. GEOGRAPHICAL DISTRIBUTION: Asia (China, India (Uttar Pradesh), Japan, Korea, Turkey, USSR (Caucasus); Europe (Belgium, France, Greece, Hungary, Italy, Portugal, Spain, Switzerland, USSR (Ukraine), Yugoslavia); N. America (Canada (British Colombia, Ontario), USA (E. including Florida, California, Oregon and Washington) (CMI Map 66, ed. 4, 1973) TRANSMISSION: The slimy conidia are spread in water and carried long distances by birds and insects. The ascospores are air dispersed; acospore discharge has been described (59, 471).

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.

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