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75 years of the chestnut blight fungus Cryphonectria parasitica (Murr.) Barr in Europe
82-85Views:171The 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.
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Examination of the plum psyllid (Cacopsylla pruni Scopoli), a vector of European Stone Fruit Yellows (ESFY) phytoplasma in the countryside of Boldogkőváralja (Hungary)
5-11Views:211European Stone Fruit Yellows(ESFY) phytoplasma disease on apricot was identified by molecular methods for the first time in 1992 in Hungary. Currently, the pathogen is known as’ Ca. Phytoplasma prunorum’. Since, the pathogen become wide-spreaded and manyof the apricot-plantations had to be eliminated. In 2009 and 2010 in the countryside of Boldogkőváralja the infection of the apricot-plantations was about 77%. As the disease spreading and causing large damages, we studied the roleo fpossible vector,the plum psyllid (Cacopsylla pruni Scopoli) in the areas of Boldogkőváralja, North-East-Hungary. Studies were done in the year of 2016, monitoring the behaviour of the psyllids in four different areas, and caught 41 them for further examination. We collected plant samples from those apricot trees, on which the plum psyllids were caught.
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Irén Dobos horticulturalist-teacher plant protection engineer expert awarded by Antal Gulyás medallion for crop protection" in 2015 (laudation)
8-10Views:168The Public Utility for Development of Crop Protection Teaching (NOFKA) and The Hajdú-Bihar County Regional Association of Hungarian Chamber of Crop Protection Specialists and Plant Doctors established a joined Award Committee in 2011, which intend to serve as moral appreciation to prominent persons with excellent achievements by awarding the „Antal Gulyás medallion for crop protection” which are available for outstanding teachers, researchers, and practical crop protection specialists. In 2015 dr. Irén Dobos horticulturist- teacher and plant doctor has been decorated with the „Antal Gulyás medallion for crop protection” for her “excellence in integrated plant protection practical research activity and effective knowledge transfer”.
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Biological control of sweet chestnut on Pécsbánya, Hungary
77-81Views:194The 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.
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Examination of the American grapevine leafhopper (Scaphoideus titanus Ball) in Debrecen and Micske (Misca, West Romania)
77-81Views:133Grapevine flavescence dorée (FD) was detected first in Hungary in 2013 in Zala County (South-West-Hungary). The disease is a serious danger for grapevine growing and grapevine propagating production. In 2014, the pathogen has been found in several new places in Hungary, viz. in Vas and Fejér Counties, and it was also detected in the former location in Zala County. The american grapevine leafhopper (Scaphoideus titanus) is the main vector of the disease. This pest was detected first in Hungary in 2006 and then it has spread all over the country. Since we have not detailed distribution data of this pest in surroundings of Debrecen, therefore we made observations in this region in 2014. The presence of the pest was confirmed by yellow sticky cards in two locations in Debrecen and another site in West Romania near to Hungarian border. We found that S. titanus is present in each sampled sites that cause serious potential danger for the appearance and spread of Grapevine flavescence dorée (FD) in this region.
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Review of the biology of plant psyllid (Cacopsylla pruni, Scopoli 1763), and its role in the spreading of European stone fruit yellows, ESFY-phytoplasma with Hungarian data
25-33Views:295The European stone fruit yellows (ESFY) phytoplasma disease caused by pathogen ’Ca. Phytoplasma prunorum’ induces serious damages in cherry, sour cherry, peach, and apricot orchards mostly in Europe. Its known vector is the plum psyllid (Cacopsylla pruni). Many articles report on the biology (morphology, taxonomy, life cycle etc.) and the method of transmission of the pathogen by the vector, and the possibilities of their control. This paper reviews our knowledge about the vector, and summarises the results of an inland research carried out in a northeastern Hungarian apricot orchards. Our goal was to show some important data for the farmers or anyone who is interested in this disease and its vector. And give some known method that we can protect our orchards against them to prevent the appearance of the disease. As the psyllid that became infected with the pathogen can hold its infectionous capacity during their lifetime, it is very important to have enough knowledge about their lifecycle, that we can determine the right time and method to control them. We also have to know how to identify them; therefore, this paper lists several important data which can be helpful. The most important keys of identification are their wing color, which dark borwn in the apex and brown is in the remaining part of the forewing. The length of the antennae is also an important factor, since other genuse’s species have longer antennae than twice the width of the head. C. pruni has as long antennae as twice the width of the head. They return to Prunus species in early spring and we have to protect our orhards in this period against them. We have to use preparations with a knock down effect on them to prevent the inoculation of the pathogen into the trees in our orchards.
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Distribution of the American grapevine leafhopper (Scaphoideus titanus Ball 1932) in surroundings of Nagyvárad (Oradea, West Romania) and Debrecen (East Hungary)
39-44Views:159The first European appearance of american grapevine leafhopper (Scaphoideus titanus), which is the vector of Grapevine Flavescence Dorée phytoplasma (‘Ca. Phytoplasma vitis’), were detected in France in 1924. The leafhopper has been distributed since 2006 in Hungary and now it occurs in the whole country, while the first record of the phytoplasma was published in 2013.
We studied the distribution of the leafhopper in surroundings of Nagyvárad (Oradea, West Romania) in 2015 and surroundings of Debrecen (East Hungary) in 2016. During the studies 17 sites were sampled. The leafhoppers were found in six Romanian places with relatively low abundances while it occurs in all studied Hungarian sites and two of them showed extremely high frequenncy. -
Studies of Cryphonectria parasitica (MURR.) BARR subpopulations on Quercus petraea in Ukraine
70-75Views:95Chryphonectria 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.
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Dieback of apricot plantations caused by 'Ca. Phytoplasma prunorum' in Borsod-Abaúj-Zemplén county (Northern-Hungary)
34-41Views:106Plant diseases caused by phytoplasmas have increasing importance in all over the world for fruit growers. Lately, phytoplasma diseases occur on many fruit varieties and responsible for serious losses both in quality and quantity of fruit production. In the long-run these diseases cause destruction of fruit trees. The apricot phytoplasma disease (Ca. Phytoplasma prunorum) was first reported in Europe in 1924 from France. In 1992 the disease has also been identified in Hungary. On the base of growers' signals serious damages of "Candidatus Phytoplasma prunorum" Seemüller and Schneider, 2004 (formerly: European stone fruit yellows phytoplasma) could be observed in different stone fruit plantations in the famous apricot-growing area nearby Gönc town, Northern-Hungary. Field examinations have been begun in 2009 in several stone fruit plantations in Borsod-Abaúj-Zemplén County mainly in Gönc region which is one of the most important apricot growing regions in Hungary, named “Gönc Apricot Growing Area”. Our goals were to diagnose the occurrence of Ca. Phytoplasma prunorum on stone fruits (especially on apricot) in the North-Hungarian growing areas by visual diagnostics and confirm data by laboratory PCR-based examinations. All the 28 collected samples were tested in laboratory trials and at 13 samples from apricot, peach, sour cherry and wild plum were confirmed the presence of phytoplasma (ESFY). On the base of observations it seems evident that the notable losses caused by "Ca. Phytoplasma prunorum" is a new plant health problem to manage for fruit growers, especially apricot producers in Hungary.
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Inhibition of the spread of Sclerotinia sclerotiorum in aquaponics
5-8Views:200Sclerotinia sclerotiorum, which causes white mold, is a widespread pathogen. In 2020, a new host plant of this fungus, the watercress (Nasturtium officinale) was identified in Hungary in an aquaponic system. During the cultivation of watercress S. sclerotiorum was detected on the plant, the fungus caused a 30% yield loss. Fungicides should not be used against fungi in aquaponic systems. Non-chemical methods of integrated pest management should be used. These include biological control (resistant species, predators, pathogens, antagonist microorganisms), manipulation of physical barriers, traps, and the physical environment. In the aquaponic system, the removal of the growing medium (expanded clay aggregate pellets) solved the damage of Sclerotinia sclerotiorum 100%. By removing the expanded clay aggregate pellets, the environmental conditions became unfavorable for the development and further spread of the S. sclerotium fungus.
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Examination of the efficacy of different fungicides against Macrophomina phaseolina and Sclerotinia sclerotiorum in laboratory conditions
21-24Views:188Macrophomina phaseolina and Sclerotinia sclerotiorum are two significant fungal pathogens of sunflower. M. phaseolina causes charcoal rot and ashy stem blight in several important crop species. Sclerotinia sclerotiorum causes white mold disease which can occur as middle stalk rot, head rot and premature plant death. Due to the wide host range of the two pathogens and their survival structures, crop rotation cannot provide sufficient protection against them. In our experiment, we selected two fungicides, Mirage and Prosaro, which are widely used in practice, and we tested their efficacy against the two pathogens. The efficiency of these fungicides was tested at a concentration of 10; 20; 50; 100 and 500 ppm. The Prosaro totally inhibited the mycelial growth of both pathogens at a concentration of 50 ppm, 100 ppm and 500 ppm. The Mirage caused total mycelial growth inhibition in all treatments against both pathogens.
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Investigation of the mycelial compatibility of Macrophomina phaseolina in the Carpatian Basin
25-28Views:100Macrophomina phaseolina is a globally widespread fungal pathogen. The fungus has a very wide range of hosts. Under optimal conditions, M. phaseolina can cause serious damage tothe host plants. In this study, the mycelial compatibility of different M. phaseolina isolates was investigated. From 2019 to 2021, 12 sunflower samples were collected from different regions of the Carpathian Basin, 9 samples from Hungary, 1 sample from Austria, and 2 samples from Slovakia. The genetic variability of the pathogen is a critical problem in plant protection. Two compatible pathogen strains can easily exchange their genetic material for each other, which can lead to the development of resistance. All collected samples (12) were tested to examine their compatibility. Isolates from all tested samples were paired with isolates from all other samples thus, a total of 66 pairings were made. During the examinations of mycelial compatibility, only 20 pairs of all possible pairings were found to be incompatible, and all others (46) were found to be compatible.
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Examination of different fungicides against Macrophomina phaseolina in laboratory conditions
65-69Views:124In Hungary, sunflower is the third most important arable crop, which has a lot of pathogenic fungi. One of these fungi is the Macrophomina phaseolina, which is a well-known fungus in all over the world, since this pathogen has more than 700 host plants. In Hungary, several host plants can be found as well. The M. phaseolina produces microsclerotia, which can survive in the soil and residues for almost 10 years. For now, there is no efficient treatment against this pathogen because of this fungus, since it is extremely resistant and cannot be destroyed easily. The only effective treatment against the fungus is genetic defence. In this study, three different fungicides were tested in vitro against the fungus. The Mirage (prochloraz) seemed to be the most effective fungicide as it completely arrested the hyphal growth. In contrast, the Amistar Xtra (azoxystrobin and ciprochonazol) has only a minor effect on the growth of M. phaseolina. Thirdly, the Retengo (pyrachlostrobin) arrested the hyhpal growth of the fungus with 71% at 100 ppm, in other words, the use of this fungicide seems promising.
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Phytoplasma infection status survey in plum psyllid (Cacopsylla pruni) population
45-48Views:127European Stone Fruit Yellows (ESFY) phytoplasma disease causes an increasing amount of damage. This is especially true to the Gönci growing region. The insect vector of the disease, which has been shown to have a vector role during transmission experiments, is the plum psyllid (Cacopsylla pruni). In 2018, during the swarming period of plum psyllid, in 3 different settlements (Boldogkőváralja, Nagyvárad and Bekecs) 265 psyllidswere collected, from which 165 were plum psyllid. Molecular biology studies showed 106 individuals infected with phytoplasma, of which 20 were males and 86 were females.