Measuring resistance of chestnut trees to chestnut blight

1992 ◽  
Vol 22 (4) ◽  
pp. 568-571 ◽  
Author(s):  
Sandra L. Anagnostakis
Keyword(s):  
Quantitative Assessment ◽  
First Generation ◽  
Chinese American ◽  
American Chestnut ◽  
Chestnut Blight ◽  
Japanese American ◽  
Individual Tree ◽  
Chestnut Blight Fungus ◽  
Tree Resistance ◽  
Virulent Strains

Four species of chestnut trees and four kinds of hybrids were inoculated with two virulent strains of the chestnut blight fungus (Cryphonectriaparasitica (Murr.) Barr). Rate of canker expansion was measured over 114 days (June–September), and rate change was used as a quantitative assessment of individual tree resistance. Cankers on two typical American chestnut trees (Castaneadentata (Marsh.) Borkh.) expanded at a rate of 1 mm/day. Expansion rates on Chinese chestnut (Castaneamollissima Blume) ranged from 0.2 to 0.6 mm/day, and the rates on two Japanese chestnut trees (Castaneacrenata Siebold & Zucc.) were 0.08 to 0.2 mm/day. Our single Henry chestnut (Castaneahenryi (Skan) Reh. & Wilson) tree allowed rates of 0.3 and 0.8 mm/day. Most rates on American–Chinese and Japanese–American hybrids were from intermediate between rates on Asian and American trees to near the rates on American trees. However, a first-generation backcross of Chinese–American × American only allowed expansion rates of 0.3 and 0.4 mm/day, similar to the lowest rates on Asian trees.

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.

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.

Effects of osmotic potential on virulent and hypovirulent strains of the chestnut blight fungus

1995 ◽  
Vol 25 (6) ◽  
pp. 1024-1029 ◽  
Author(s):  
S. Gao ◽  
L. Shain
Keyword(s):  
Osmotic Potential ◽  
Mycelial Growth ◽  
Companion Paper ◽  
Conidial Germination ◽  
Chestnut Blight ◽  
Chestnut Blight Fungus ◽  
Virulent Strains ◽  
Agar Media ◽  
Cornmeal Agar ◽  
Osmotic Potentials

Mycelial growth and conidial germination of two virulent and four isogenic hypovirulent strains of Cryphonectriaparasitica (Murr.) Barr were monitored on cornmeal agar media osmotically adjusted with NaCl, KCl, sucrose, or a salt mixture of NaCl–KCl–Na2SO4 of 5:3:2. Mycelial growth generally was not inhibited on KCl or sucrose adjusted media with an osmotic potential above −2.0 MPa. Mycelial growth generally was inhibited at this osmotic potential, however, on those media that contained sodium in the osmoticum. While conidial germination was more sensitive than mycelial growth to sodium, conidia were more tolerant than mycelia to osmotic potentials less than −2.0 MPa when media were adjusted with KCl or sucrose. Conidia of all strains germinated on media adjusted to −6.0 MPa with these two osmotica after incubation for 48 h but not 24 h at 25 °C. Hypovirulent strains generally reacted similarly to their isogenic virulent strains with regard to reduced osmotic potential. Because the lowest osmotic potential of chestnut (Castaneadentata (Marsh.) Borkh.) bark observed in monthly samples was −2.0 MPa (see companion paper), it appears that water stress has little direct impact on the pathogen during pathogenesis.

scholarly journals Effect of the media on morphology of Cryphonectria parasitica (Murr.) Barr isolates and their Vegetative Compatibility Groups

2015 ◽  
pp. 38-42
Author(s):  
Gabriella Kovács ◽  
László Radócz
Keyword(s):  
Cryphonectria Parasitica ◽  
Vegetative Compatibility ◽  
Bark Extract ◽  
Chestnut Blight ◽  
Vegetative Compatibility Groups ◽  
Infested Area ◽  
Chestnut Blight Fungus ◽  
Virulent Strains ◽  
Different Types ◽  
The Media

The most dangerous pathogen for the European and American chestnuts is the blight fungus Cryphonectria parasitica (Murrill) Barr. Short after its introduction a big number of chestnut trees were destroyed on the infested area. The control could be really complicated, because of the numerous vegetative compatibility groups of the fungus. There is a type that carries a mycovirus viz. hypovirus in the cytoplasm. We are able to control effectively this pathogen by using mycovirus-carrying strains (called hypovirulent fungal strains also). In laboratory it is easy to multiply the virulent and the hypovirulent strains of the fungus but do not easy to differentiate colonies visually on simple PDA medium. During our research, we tested different types of media, based on potato and chestnut bark extract respectively. It was observed that on potato medium the virulent strains produce more orange pigments. So it is more easy to differentiate virulent or hypovirulent isolates of chestnut blight fungus based on colony colour and morphology.

Conidia of hypovirulent strains of Cryphonectriaparasitica differ in their potential for biocontrol of chestnut blight

1992 ◽  
Vol 22 (9) ◽  
pp. 1338-1342 ◽  
Author(s):  
K.L. Scibilia ◽  
F.V. Hebard ◽  
L. Shain
Keyword(s):  
Virulent Strain ◽  
Culture Collection ◽  
American Chestnut ◽  
American Type Culture Collection ◽  
Chestnut Blight ◽  
Virulent Strains ◽  
Hypovirulent Strain

Conidia from eight hypovirulent strains of Cryphonectriaparasitica (Murr.) Barr were suspended in water and applied to the bark of American chestnut (Castaneadentata (Marsh.) Borkh.) trees. Cankers were initiated with mycelium of virulent strains isogenic to the applied conidia. Hypovirulent strains differed significantly in the ability of their conidia to putatively convert isogenic virulent strains in cankers, as indicated by the recovery of cultures with hypovirulent morphology from challenged cankers. A tank mix of conidia from two hypovirulent strains in different conversion groups putatively converted significantly more cankers initiated by isogenic virulent strains than did separate applications of conidia from these strains, particularly when the second application was delayed by 2 weeks. Cankers initiated on excised stems with virulent strain Ep 155 (American Type Culture Collection 38755) yielded cultures with hypovirulent morphology after application of conidia from isogenic hypovirulent strain Ep 780 at densities as low as 50 and 700 conidia/cm2 for inoculations sealed or not sealed with latex caulk, respectively.

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 Dynamics of Cryphonectria hypovirus Infection in Chestnut Blight Cankers

2014 ◽  
Vol 104 (9) ◽  
pp. 918-925 ◽  
Author(s):  
Sarah Franziska Bryner ◽  
Simone Prospero ◽  
Daniel Rigling
Keyword(s):  
Virus Infection ◽  
Cryphonectria Parasitica ◽  
Chestnut Blight ◽  
Seedling Mortality ◽  
Chestnut Blight Fungus ◽  
European Chestnut ◽  
Virulent Strains ◽  
Coppice Forest ◽  
Cryphonectria Hypovirus ◽  
Over Time

Virulent strains of the chestnut blight fungus Cryphonectria parasitica cause lethal bark cankers on chestnut trees. Infection of C. parasitica with Cryphonectria hypovirus 1 in Europe biologically controls this disease, leading to nonlethal and inactive cankers. Unexpectedly, virus-free C. parasitica strains have been isolated from inactive cankers. In this study, we compared the virulence of virus-infected and virus-free C. parasitica strains isolated from either inactive or active cankers on chestnut seedlings and sprouts. In the seedling experiment, we assessed canker growth and seedling mortality. In the sprout experiment, we also assessed canker growth and made fungal reisolations to determine virus infection and immigration of foreign vegetative compatibility (vc) types over a period of 13 years in a coppice forest. Overall, the virulence of virus-free C. parasitica strains isolated from inactive versus active cankers did not differ. Significant differences were only attributed to virus infection. Virus infection and fungal strain composition in cankers changed over time. Foreign vc types immigrated into cankers and virus-free cankers became virus-infected within a few years. Most of the cankers were callused over time and became inactive. However, we observed that the virus did not always persist in these cankers. This study demonstrates that virus spread occurs effectively in European chestnut forests and that this biocontrol system is highly dynamic.

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.

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