Bacillus Subtilis an Endophyte of Chestnut (Castanea Sativa) as Antagonist Against Chestnut Blight (Cryphonectria Parasitica)

1997 ◽  
pp. 331-337 ◽  
Author(s):  
Eva Wilhelm ◽  
Wolfgang Arthofer ◽  
Roland Schafleitner ◽  
Birgit Krebs
Keyword(s):  
Bacillus Subtilis ◽  
Castanea Sativa ◽  
Cryphonectria Parasitica ◽  
Chestnut Blight

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 Changes in Cryphonectria parasitica Populations Affect Natural Biological Control of Chestnut Blight

2018 ◽  
Vol 108 (7) ◽  
pp. 870-877 ◽  
Author(s):  
Marin Ježić ◽  
Jelena Mlinarec ◽  
Rosemary Vuković ◽  
Zorana Katanić ◽  
Ljiljana Krstin ◽  
...  
Keyword(s):  
Plant Pathogens ◽  
Infected Plant ◽  
Castanea Sativa ◽  
Cryphonectria Parasitica ◽  
Chestnut Blight ◽  
Native Plant ◽  
Native Plant Species ◽  
Sweet Chestnut ◽  
Tripartite Interactions ◽  
Disease Management Strategy

Invasive species, especially plant pathogens, have a potential to completely eradicate native plant species and remodel landscapes. Tripartite interactions among sweet chestnut (Castanea sativa), chestnut blight-causing invasive fungus Cryphonectria parasitica, and hyperparasitic virus Cryphonectria hypovirus 1 (CHV1) were studied in two populations. The number of different vegetative compatibility (vc) types of C. parasitica more than doubled over the 10 years, while the hypovirulence incidence dropped in one population and slightly increased in the other one. Over the course of our 3-year monitoring experiment, the prevalence of hypovirulent isolates obtained from monitored cankers increased slowly (i.e., more hypovirulent isolates were being obtained from the same cankers over time). Within studied cankers, considerable changes in vc type and CHV1 presence were observed, indicating a highly dynamic system in which virulent and hypovirulent mycelia, sometimes of discordant vc types, often appeared together. The increase in hypovirulence prevalence did not have any observable curative effect on the cankers and, occasionally, reactivation of healed cankers by new, virulent C. parasitica isolates was observed. Both short- and long-term observations and revalidation of the infected plant populations are necessary to accurately estimate disease progress and formulate an adequate disease management strategy.

scholarly journals New finds of Cryphonectria parasitica and the first record of chestnut blight on red oak Quercus rubra L. in the Czech Republic

2012 ◽  
Vol 51 (No. 6) ◽  
pp. 256-258 ◽  
Author(s):  
P. Haltofová ◽  
L. Jankovský ◽  
D. Palovčíková
Keyword(s):  
Czech Republic ◽  
Castanea Sativa ◽  
First Record ◽  
Cryphonectria Parasitica ◽  
Chestnut Blight ◽  
Red Oak ◽  
The Czech Republic ◽  
Sweet Chestnut ◽  
New Localities ◽  
Endothia Parasitica

The causal agent of the chestnut blight, the fungus Cryphonectria parasitica (Murrill) M. E. Barr (syn. Endothia parasitica (Murrill) P. J. Anderson et H. W. Anderson), was found out at new localities in the Czech Republic. The chestnut blight was observed for the first time in the Czech Republic in 2002. Two new localities were discovered in southern Moravia in May and June 2004. The disease was identified both on the sweet chestnut (Castanea sativa Mill.) and on the red oak (Quercus rubraL.). Infected trees were treated according to the order of the State Phytosanitary Administration of the Czech Republic. 

scholarly journals Studies of Cryphonectria parasitica (MURR.) BARR subpopulations on Quercus petraea in Ukraine

2011 ◽  
pp. 70-75
Author(s):  
László Radócz ◽  
Gábor Tarcali ◽  
László Irinyi ◽  
Gábor Görcsös
Keyword(s):  
Fungal Pathogens ◽  
Castanea Sativa ◽  
Cryphonectria Parasitica ◽  
Quercus Petraea ◽  
Carpathian Basin ◽  
Chestnut Blight ◽  
Oak Trees ◽  
Compatibility Group ◽  
Laboratory Examinations ◽  
Blight Disease

Chryphonectria parasitica (Murr.) Barr, the casual agent of chestnut blight disease, which is one of the most important fungal pathogens of chestnut (Castanea sativa). The disease seriously affected the chestnut in Northern-America and in Europe as well. It is important to mention that the pathogen does not only infect the chestnut but oak species (Quercus spp.) also. In the Carpathian-Basin, the chestnut is endemic in the Mecsek mountains, in Zala, in Somogy counties but it also can be found in the Danube-Bend. In the Carpathian-Basin (outside Hungary) the chestnut is found in Slovakia, Ukraine, Romania. In our study bark samples infected by Cryphonectria parasitica were collected from Bobovyshche, Serednje and Rostovjatica (Ukraine). The rate of infected chestnut tree were higher than 90% around Bobovyshche and beside chestnut, the symptoms were detected on oak trees as well. We collected bark samples from chestnut and oak as well and then we isolated the pathogen Cryphonectria parasitica in the lab of University of Debrecen. Symptomatological observations, laboratory examinations on fungus morphology, as well as comparisons of ITS sequency homology were made and approved that the causal agent of new disease was Cryphonectria parasitica. Our results proved that the Cryphonectria. parasitica infects oak trees beside chestnut in the Carpathian-Basin. Further studies are needed to determine the VCG (Vegatative Compatibility Group) group of the Cryphonectria parasitica found on oak trees. 

scholarly journals Genetic diversity of Cryphonectria parasitica causing chestnut blight in South Tyrol (northern Italy)

2022 ◽  
Author(s):  
Farooq Ahmad ◽  
Sanja Baric
Keyword(s):  
Genetic Diversity ◽  
Diversity Index ◽  
Castanea Sativa ◽  
Cryphonectria Parasitica ◽  
Northern Italy ◽  
Chestnut Blight ◽  
Type Locus ◽  
South Tyrol ◽  
Its Sequence Analysis ◽  
Hyphal Anastomosis

AbstractEuropean chestnut (Castanea sativa) is threatened by the invasive fungus Cryphonectria parasitica, which causes chestnut blight. The virulence of the fungus can be reduced by a group of mycoviruses that can spread among vegetatively compatible strains through hyphal anastomosis. Hypovirulent isolates are used as biocontrol agents, but their efficiency can be diminished by restricted hyphal anastomosis if the variability of vegetative compatibility (vc) types in a population is high. Sexual reproduction could increase the vc type diversity and further complicate biocontrol in a region. Therefore, knowledge of genetic diversity of C. parasitica is important to assess the effectiveness of a biological control program. The present study was performed in the Autonomous Province of Bozen-Bolzano (South Tyrol) in northern Italy, where chestnut cultivation provides an additional income to farmers. The genetic characterization of C. parasitica isolates from 35 chestnut stands and one forest population in different districts of South Tyrol was performed based on the analysis of vegetative incompatibility loci, the mating type locus, and the internal transcribed spacer (ITS) region. In this study, a total of 23 different vc types were found all over South Tyrol with a Shannon diversity index of 1.86. EU-2, EU-1, and EU-13 were the most widespread vc types comprising 51%, 13%, and 9% of the fungal isolates, respectively. Both mating types were present in the region with a ratio close to 1:1. Three different haplotypes were identified based on ITS sequence analysis, which pointed to two introduction events of the fungus to the region and allowed placing C. parasitica from South Tyrol into a larger phylogeographic context.

scholarly journals Management of Chestnut Blight in Greece Using Hypovirulence and Silvicultural Interventions

Forests ◽  
2018 ◽  
Vol 9 (8) ◽  
pp. 492 ◽  
Author(s):  
Stephanos Diamandis
Keyword(s):  
Biological Control ◽  
Castanea Sativa ◽  
Pilot Project ◽  
Cryphonectria Parasitica ◽  
Chestnut Blight ◽  
Sweet Chestnut ◽  
Central Greece ◽  
Clear Cutting ◽  
Castanea Sativa Mill ◽  
Nut Production

Sweet chestnut (Castanea sativa Mill.) is an important tree for Greece. The invasive fungus Cryphonectria parasitica, which causes chestnut blight, was first found in Central Greece in 1963. It has since spread all over the country, significantly reducing the national annual nut production. The increasing decline of forests and orchards due to the disease led to a project in 1995, which aimed at studying the feasibility of applying biological control. A prerequisite study of the existing vegetative compatibility types of the pathogen showed only four, and their distribution was mapped. A pilot project (1998–2000) that consisted of clear cutting heavily infected coppice stands and introducing hypovirulence to the remainder was implemented on Mt. Athos on a 7000 ha sweet chestnut forest. Two evaluations (in 2003 and 2011) revealed that hypovirulence was established in the sweet chestnut forests and spread more or less homogeneously. A nationwide project introducing hypovirulence to 29 counties was implemented in two, 3-yr-periods 2007–2009 (17 counties) and 2014–2016 (12 counties). The new evaluations showed that hypovirulence spread profoundly and forests and orchards started recovering. The appearance of natural hypovirulence cannot be predicted. Introduced hypovirulence and silvicultural interventions can be used to manage the disease. It is the responsibility of the forest/orchard manager to decide whether to wait for appearance of natural hypovirulence, or to introduce it for a faster decline in disease.

scholarly journals Hail-Induced Infections of the Chestnut Blight Pathogen Cryphonectria parasitica Depend on Wound Size and May Lead to Severe Diebacks

2020 ◽  
Vol 110 (7) ◽  
pp. 1280-1293
Author(s):  
Guglielmo Lione ◽  
Luana Giordano ◽  
Massimo Turina ◽  
Paolo Gonthier
Keyword(s):  
Logistic Model ◽  
Castanea Sativa ◽  
Cryphonectria Parasitica ◽  
Chestnut Blight ◽  
Risk Of Infection ◽  
North West ◽  
The North ◽  
Single Location ◽  
Entry Points ◽  
Cryphonectria Hypovirus

This study combined phytosanitary surveys, laboratory analyses, and mathematical modeling to show how hail-induced wounds can foster the infections of the blight pathogen Cryphonectria parasitica, locally associated with extensive dieback of chestnut (Castanea sativa). Orchards and coppices located within and outside the assessed dieback area in a single location in the North West of Italy were inspected to appraise the abundance of hail-induced wounds and C. parasitica infections. The incidence of C. parasitica was significantly higher within the dieback area compared with outside (92% versus 60%; P < 0.05). Hail-induced wounds were observed on small branches and shoots of all trees sampled within the dieback area, whereas they were less abundant outside (20% of trees), suggesting either that the dieback was directly associated with the injuries caused by the hailstorms or that those injuries may have facilitated infections of C. parasitica. Isolations conducted on 359 branches and shoots showed that hail-induced wounds served as infection courts for C. parasitica and that infections depended on the size rather than on the number of hail wounds. We fitted a logistic model showing that hail-induced wounds whose perimeter was larger than 66 mm were at particular risk of C. parasitica infection. A newly designed geometrical-based model is proposed to relate hailstones size, hail wound perimeter, and the risk of infection. We established that hail-induced wounds are entry points for virulent and hypovirulent strains of C. parasitica, since 6.5% of isolates were infected by Cryphonectria hypovirus-1.

scholarly journals The development of population structure of Cryphonectria parasitica on European chestnut (Castanea sativa Mill.) in the Experimental Castanetarium Horné Lefantovce, observed over a 12-year study period

2009 ◽  
Vol 36 (No. 2) ◽  
pp. 55-60 ◽  
Author(s):  
K. Adamčíková ◽  
M. Kobza ◽  
G. Juhásová
Keyword(s):  
Population Structure ◽  
Castanea Sativa ◽  
Morphological Characters ◽  
Cryphonectria Parasitica ◽  
Chestnut Blight ◽  
Experimental Plot ◽  
Disease Symptoms ◽  
European Chestnut ◽  
Blight Disease ◽  
First Time

: We studied occurrence of chestnut blight disease in the Experimental Castanetarium Horné Lefantovce, SW Slovakia. The study ran in years 2006–2007 on a set consisting of 889 chestnut trees growing in the clonal orchard on Biological Plot 105. From this number, 857 trees were found healthy without disease symptoms. The chestnut blight disease was identified on 32 of them. The infected trees were examined for presence of pycnidia and perithecia of the causal agent. In all positive cases, the observed morphological characters indicated virulency of the obtained isolates. No hypovirulent isolate was detected on the evaluated experimental plot. In total, six vegetative compatibility (vc) types were specified in the sample consisting of 31 isolates. Our vc types corresponded to the European vc types EU 2, EU 12, EU 13, EU 14, EU 17, EU 19. Two vc types – EU 2 and EU 19 – were dominant. Vc type EU 19 accounted 35.5% and EU 2 32.2% of isolates. The vc type EU 19, which was the most frequent one in the evaluated site, was detected in Slovakia for the first time.

scholarly journals Biologische Bekämpfung des Kastanienrindenkrebses auf der Alpennordseite der Schweiz|Biological control of chestnut blight north of the Swiss Alps

2007 ◽  
Vol 158 (11) ◽  
pp. 342-348
Author(s):  
Ursula Heiniger
Keyword(s):  
Biological Control ◽  
Castanea Sativa ◽  
Cryphonectria Parasitica ◽  
Vegetative Compatibility ◽  
Swiss Alps ◽  
Chestnut Blight ◽  
Biologische Bekämpfung ◽  
Chestnut Blight Fungus ◽  
Low Rate

Since 1986 several isolated stands of chestnut (Castanea sativa) located north of the Swiss Alps have been infected with the chestnut blight fungus (Cryphonectria parasitica). At all sites (1–3), the diversity of the vegetative compatibility types was low. To control the disease, the hypovirus CHV1 was introduced at seventeen sites in five cantons. In total, 571 cankers were treated with local C. parasitica isolates containing CHV1. Re-inspection of the cankers one to two years after treatment demonstrated that the percentage of active cankers was significantly reduced in three cantons. Re-isolations of C. parasitica showed that the hypovirus persisted in 33% to 75% of the treated cankers and was disseminated to new cankers at a low rate. The difficulties and the potential of hypovirus treatment of small chestnut stands are discussed.

scholarly journals Role of Fresh Dead Wood in the Epidemiology and the Biological Control of the Chestnut Blight Fungus

Plant Disease ◽  
2019 ◽  
Vol 103 (3) ◽  
pp. 430-438 ◽  
Author(s):  
Joana Beatrice Meyer ◽  
Loïc Chalmandrier ◽  
Fabio Fässler ◽  
Christopher Schefer ◽  
Daniel Rigling ◽  
...  
Keyword(s):  
Biological Control ◽  
Dead Wood ◽  
Biocontrol Agent ◽  
Castanea Sativa ◽  
Cryphonectria Parasitica ◽  
Chestnut Blight ◽  
Chestnut Blight Fungus ◽  
Study Sites ◽  
Cryphonectria Hypovirus

The invasive fungus Cryphonectria parasitica, the causal agent of chestnut blight, is able to survive and sporulate on the bark of fresh dead Castanea sativa wood for at least 2 years. Here, we experimentally investigated the role of fresh dead wood in the epidemiology of chestnut blight, specifically in the spread of the hyperparasitic virus Cryphonectria hypovirus 1, which acts as biocontrol agent of C. parasitica. A total of 152 artificially initiated, virulent bark cankers in four chestnut stands were treated with virus-infected asexual spores originating either from sporulating dead wood or from a spore suspension. Molecular markers for both the virus and the fungal carrier were used to examine the spread of the applied biocontrol virus. Fourteen months after treatment, 42 to 76% of the conidial spray-treated cankers and 50 to 60% of the cankers exposed to a sporulating dead stem had been virus infected by the applied hypovirulent conidia in all four study sites. Virus infection reduced canker expansion and promoted canker healing (callusing). Thus, fresh chestnut dead wood may play an important role in supporting the successful spread of natural hypovirulence in chestnut forests. Further, combined with the application of virus-infected conidial suspensions, it may help promote the establishment of artificially released hypoviruses in chestnut stands to control chestnut blight.

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