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• Prevalence of banana diseases and post-harvest losses in Kenya, and biocontrol potential of arbuscular mycorrhizal fungi against Fusarium wilt

  62-73.

  H. K. Kamore

  E. M. Njeru

  S. B. Nchore

  R. O. Ombori

  J. M. Muthini

  J. Kimiti

  Views:

  876

  The demand for bananas (Musa spp.), which is ranked as the most important fruit crop in Kenya has been on the rise owing to both their dietary contribution and income generation. Meeting this demand has however been hampered by losses during production or post-harvest. This study assessed banana disease and post-harvest losses in leading producing counties in Kenya namely; Kisii, Nyamira and Embu. The study also assessed the efficacy of Rhizophagus irregularis in controlling Fusarium oxysporum f.sp. cubense. Structured questionnaires were used to collect data on post-harvest losses. Disease scoring tables, charts and photos were used to confirm observed symptoms and hence, disease occurrence and severity. AMF biocontrol efficacy experiment was conducted using tissue culture bananas grown in the greenhouse. The study revealed that most smallholder farmers were unaware of the causes or the prevalence of post-harvest losses. The findings also revealed a significant difference (p<0.05) in the severity of banana diseases across various cultivars from the three counties. The AMF treated bananas showed a significant difference (p<0.05) in plant height, total leaf area and chlorosis in comparison to other treatments. The study also revealed a reduction of Fusarium’s pathogenic effects including chlorosis, reduced leaf surface area and eventual necrosis.

• In vitro comparative study of two Arundo donax L. ecotypes’ selenium tolerance

  119-122.

  É. Domokos-Szabolcsy

  N. Abdalla

  T. Alshaal

  A. Sztrik

  L. Márton

  H. El-Ramady

  Views:

  617

  Selenium tolerance of two somatic embryo-derived Arundo donax L. ecotypes (Blossom, 20SZ) were compared in in vitro culture. Sodium-selenate (1 – 100 mg L-1) as known the most phytoavailable selenium form and the less studied red elemental nanoselenium (100 mg L-1) were applied as selenium treatments. Basis on the results Blossom ecotype seemed to be more sensitive to the sodium-selenate than 20SZ. Inhibiting effect of selenate was effectuated above 10 mg L-1 in case of Blossom, which was manifested in decreased survival rate and growing parameters. Contrast to this 20SZ could tolerate the selenate ≤ 20 mg L-1 without any toxic symptoms. Lower selenate tolerance of Blossom could be explained with higher selenium accumulation. Both of two ecotypes could also uptake and accumulate the red elemental nanoselenium however in much less extent compared to selenate.

• Susceptibility of some traditional pear cultivars of Hungarian and foreign origin to the pathogenic bacterium Erwinia amylovora

  41-45.

  K. Honty

  M. Hevesi

  M. Göndör

  G. Tóth M.

  V. Bács-Várkuti

  A. Ferenczy

  Views:

  329

  Fire blight, a disease caused by the bacterium Erwinia amylovora (Burrill) Winslow et al., has been causing serious damage in Hungarian pear plantations since 1996. A prospective control measure could be the use of resistant cultivars. For that purpose ten pear cultivars have been tested under laboratory and greenhouse conditions for resistance to Erwinia amylovora strains collected in Hungary. Six of these cultivars are Hungarian ones of unknown origin, while four are traditional old varieties. Resistant cultivars should serve as germplasm for future breeding. Inoculations were made with a mixture of different pear isolates of the bacteria collected from various growing regions of Hungary (Ea 21, 23), at a density of 5x10⁸ cells/ml. Susceptibility/resistance has been assessed on the basis of intensity of blight symptoms observed on shoots, flower parts and fruits. Cultivars were assigned to three susceptibility groups (low, moderate and high). Complete resistance was not found among the cultivars tested. The highest level of resistance was found in cultivar 'Kieffer', while the other cultivars displayed either moderate or high susceptibility to infection.

• Effect of training system on the incidence of Stigmina carpophila and fruit size and weight of European plum (Prunus domestica)

  78-80.

  B. Molnár

  I. J. Holb

  Views:

  768

  In a two-year study (2017-2018), the aim was to determine the incidence of shot hole disease (Stigmina carpophila) on plum cultivar ’Čačanska lepotica’ in four different training systems with tree spacings of 4 x 1.5, 4 x 2, 5 x 2.5 and 6 x 3 m. Fruit size (width and length) and fruit weight were also assessed during harvest of fruit in the four training system. Cultivar ’Čačanska lepotica’ was susceptible to shot hole disease and showed shot hole symptoms in both years and in all training systems. In 2017, the highest disease incidence was observed in the 4 x 1.5 m plot (34% in June and 85% at the end of September). In June and July, the 6 x 3 m training system had the lowest disease incidence. In August and September, the 5 x 2.5 m training system had the smallest incidences of the disease among the training systems. In 2018, except for one assessment date (18 August) the 4 x 1.5 m plot had higher incidences than the other three training systems. Training system and years had almost no effect on fruit size, but there were some differences in fruit weight among the training systems.

• Some biological properties of new sweet cherry cultivars in Bulgaria and their susceptibility to Blumeriella jaapii

  95-97.

  M. Borovinova

  N. Christov

  J. Nyéki

  Views:

  1416

  Investigations were made on 12 sweet cherry cultivars (‘13-S-22-8’, 'Sunburst', `Kozerska'., 'NY 13791', 'Royalton', 'NY 13688', 'Hartland', `Sumerset', 'Pollax', 'Patriotka Krima', 'Castor', and `Lapins') in an experimental orchard of cherry cultivar collection in the Institute of Agriculture at Kyustendil, Bulgaria during the period of 1997-2003. The trees were planted in 1996. All cultivars were grafted on Prunus mahaleb. Four biological properties of the cultivars were assessed such as blooming time, resistance to late spring frost, fruit ripening and fruit mass. Among cultivars, a good resistance to late spring frost was observed on cultivar 'Sunburst'. The fruit mass varied between 4.2 g (cv. 'Patriotka Krima') and 8.5 g (cv. `Sunburst'). The susceptibility of the cherry cultivars to cherry leaf spot caused by Blumeriella jaapii was assessed in mid-September in each year. The estimation of the rate of attack was made according to the grade of Townsend and Neuberger. All cultivars showed symptoms of cherry leaf spot but the degree of susceptibility was different. Cultivar `Patriotka Krima' was the least susceptible, while cultivar `Somerset' was the most susceptible to Blumeriella jaapii.

• Effect of late spring frost event on nutrition aspects of a sour cherry orchard in East Hungary

  93-97.

  P. T. Nagy

  I. Kincses

  J. Nyéki

  T. Szabó

  M. Soltész

  Z. Szabó

  Views:

  1952

  Similarly to 2007, 2011 was also critical year for fruit growers in Eastern-Hungary. Serious frost damage was observed at late blooming period (6 May (T=-1.6°C)) in this region, which caused approximately 60-65% of fruit loss. The aim of this study is to investigate the effects of a spring frost event on nutrient uptake and status of the trees of a sour cherry plantation at Újfehértó. The symptoms of frost were observed visually. This visual observation was confirmed by SPAD readings. The frost affected the macroand micronutrient contents of leaves. It was found that the frost affected the nutrient uptake negatively, but the effect of it was not significantly sometimes. It can be stated that the nutrient demand of trees can be supplied only under even worse conditions.

• Apple powdery mildew caused by Podosphaera leucotricha: some important features of biology and epidemiology

  45-51.

  I. J. Holb

  Views:

  1451

  In this review, some important features of biology and epidemiology are summarised for apple powdery mildew (Podosphaera leucotricha). In the first part of the review, the geographical distribution or the pathogen are discussed, then the morphology and taxonomy of the causal organism are described. Disease symptoms or apple powdery mildew are also shown and then host susceptibility/resistance is discussed in relation to durability of resistance. In the second part of this review, the general disease cycle of powdery mildew on apple are demonstrated and some basic features of powdery mildew epidemiology (such response of the pathogen to temperature, relative humidity, and rain as well as spore production, spore dispersal, diurnal patterns and temporal dynamics of the pathogen/disease) are also given on apple host.

• Preliminary study on micro area based spatial distribution of powdery mildew in an organic apple orchard

  35-37.

  I. J. Holb

  Views:

  632

  In this study, the objective was to report a preliminary study on micro area based spatial distribution of powdery mildew in an organic apple orchard. Results showed that number of symptomatic plant part ranged between 11 and 20 on shoot and between 9 and 24 on fruit. Number of asymptomatic plant part ranged between 85 and 109 on shoot and between 133 and 206 on fruit. Disease incidence ranged between 13.8 and 17.6% on shoot and between 9.1 and 11.3% on fruit. Disease aggregation index ranged between 0.098 and 0.228 on shoot and between 0.043 and 0.108 on fruit. One of the four trees showed significant within canopy aggregation of disease for shoot powdery mildew symptoms in both years. For leaf powdery mildew, all tree exhibited random patterns in both years.

• Study of Erwinia amylovora colonization and migration on blossoms of susceptible and tolerant apple cultivars

  15-19.

  E. Mihalik

  A. Radvánszky

  L. Dorgai

  T. Bubán

  Views:

  336

  The stigmata of detached flowers of susceptible and tolerant apple cultivars were inoculated with about 10⁴ gfp labeled Erwinia amylovora . There were no apparent differences in the colonization, multiplication and survival of the bacteria on the stigmatic surface of the culivars. Bacteria were washed down to the hypanthium surface 24 hours after inoculation. The visual symptoms of the infection were the discoloration and shrinkage of the floral parts. The gradual browning associated with the infection appeared first on the surface of the hypanthium followed by the discoloration of the style. The color of the filaments turned into brown only 120 hours after the inoculation. Bacterial cells were not detected in the tissues of the styles and filaments. The traits of the hypanthium surface are of prominent importance in the progression of the infection. The wrinkled surface, the convex shape of the outer epidermal cell walls with thin cuticle and the sunken stomata helped to preserve a water film for a longer period providing medium for the motility of the bacteria in the susceptible cultivar. Bacteria were restricted to small water droplets on the flat and waxy surface of the hypanthium of the tolerant cultivar and only a few were able to enter the tissues.

  Large bacterium aggregations were detected in the intercellular spaces of the parenchyma of the susceptible cultivar 48 hours after the inoculation. In the next period the Erwinia amylovora cells gradually invaded the intercellulars of the hypanthium wall, the wall of the ovary and the pedicel. Low level of bacterium aggregation was found in the intercellulars of the tolerant cultivars. It is suggested that the progression of the infection was inhibited also by physiological factors.

• Incidence of fungal diseases on leaves of apricot and plum cultivars in Hungary

  29-31.

  I. J. Holb

  G. Drén

  S. Thurzó

  Z. Erdős

  M. Soltész

  J. Nyéki

  Z. Szabó

  Views:

  1391

  In this two-year study, incidence of Polystigma rubrum on plum, and Apiognomonia erytrostoma on apricot were evaluated on several stone fruit cultivars in Hungary. Results showed that most apricot cultivars expressed symptoms caused by A. erytrostoma, graded between 2 and 3 (10-50%) by the end of the summer in 2005 and 2006. The most tolerant apricot cultivars were Budapest and Mandulakaj­szi while the most susceptible ones were 'Magyar kajszi' and 'Piroska'. Assessments made on plum showed that most of the plum cultivars were tolerant or lowly susceptible to P. rubrum such as 'Ageni', 'Althann ringló', 'Bluefre', 'Cacanska najbolja', 'Silvia', 'Ruth Gerstetter', 'Tuleu gras' and 'Utility'. The most susceptible plum cultivars to P. rubrum were 'Besztercei clones' and 'Debreceni Muskotály'.

• Phytoplasma diseases of grapevine and the possible measures to control them

  37-43.

  M. Kölber

  Views:

  610

  Phytoplasmas are a special group of phloem-living pathogens in several plant species. Grapevine yellows (GY) is a term for phytoplasma diseases occurring on Vitis vinifera and inducing the same or very similar symptoms and causing severe losses worldwide. Flavescence Dorée (16SrV) phytoplasma (FD, species name: ‘Candidatus Phytoplasma vitis’) is considered a quarantine pest in several countries due to its epidemic character and high economic loss it provokes. The leafhopper Scaphoideus titanus is the univoltine and monophagous vector of FD. Bois noir disease caused by stolbur (16SrXII-A) phytoplasma (species name: ‘Candidatus Phytoplasma solani’) is described under different disease names in different countries. Hyalesthes obsoletus (Cixiidae) is the only proved polyphagous vector of BN. However, distribution of BN disease is increasing also on those areas where H. obsoletus is not prevalent or only in a very low number. Therefore the presence of other vectors cannot be concluded. The ‘Tuf-a’ type Stolbur phytoplasma is associated with stinging nettle (Urtica dioica) and the tuf-b type one to field bindweed (Convolvulus arvensis). There are only preventive control measures against phytoplasmas: the use of pathogen-free propagating material, hot water treatment of propagating material, as well as control of vectors and weeds. S. titanus can be efficiently controlled by insecticide treatments. However, in case of H. obsoletus, insecticides are not effective due to the biological characters and feeding habits of the vector.Weed control can reduce H. obsoletus specimen and their abundance to a certain extent. Extensive research is needed on wild hosts of GY phytoplasmas especially on BN phytoplasma and its vectors to the better understanding of their epidemiology.

• Detection and identification of phytoplasmas in peach based on woody indexing and molecular methods

  35-41.

  M. Németh

  I. Ember

  L. Krizbai

  M. Kölber

  R. Hangyál

  J. Bozsics

  Views:

  299

  Symptoms resembling phytoplasma disease have been observed on peach trees in a seed-source plantation of stone fruits in south Hungary quite recently. In this publication we report on the results of woody indexing of symptomatic peach trees on GF 305 indicator in the field and under greenhouse conditions as well as on molecular studies. Phytoplasma infection detected on GF 305 indicators in greenhouse and field indexing was confirmed by PCR. Nested PCR was conducted using universal primer pairs followed by group and subgroup specific primers for the second amplification. RFLP analysis of nested PCR products was performed using Rsal restriction enzyme. Based on the results of molecular studies it can be concluded that phytoplasmas, belonging to the European stone fruit yellows subgroup (16SrX-B) were identified in peach trees. Further studies on symptomatic peach trees originating from different parts of Hungary are in progress.

• Abnormalities of the stigma of sour cherry cultivar

  31-33.

  H. G. Davarynejad

  T. Szabó

  Z. Szabó

  J. Nyéki

  I. J. Holb

  Views:

  5104

  The objective of this study was to evaluate the ratio of blackness of the surface of stigma of sour cherry cultivars. At the full bloom time of sour cherry 100 new opened flowers were marked in the internal (Inside), external (outside), bottom and upper parts of the crown of each cultivars including sour cherry cultivars ‘Érdi bőtermő', `Debreceni bőtermő', `Kántorjánosi', 'R. clone', 'Petri', Pándy', and 'D. clone'. The trees were replicated four times. The numbers of flowers with black stigma were counted and the percentage of dead stigma was calculated. In addition, tissues of black stigmata were investigated for blossom pathogens by microscopy. After flowering time the fruit set of the marked flowers counted and then percentage fruit set was calculated. Numbers of counted flowers were between 300 and 980 depending on the four position of the tree. Black color of stigma could be seen only on three cultivars (`Debreceni bőtermő', Érdi bőtermő' and 'Petri') out of seven assessed cultivars. The highest numbers of black colored stigma were found on cultivar ‘Érdi bőtermő' which ranged between incidences of 12 and 21%. Black stigma was never able to produce a fruit set. Microscopic examination revealed no pathogens associated with black stigma. Different part of the tree resulted different amount of black stigma. Black stigma was the largest on the outer part of the tree on cv. 'Érdi bőtermő' but also bottom part of the tree also produced larger number of black stigma on cvs. `Debreceni bőtermő' and ‘Érdi bőtermő'. Though symptoms were not typical to frost damage, we believe that black stigma is probably due to environmental factors during flowering. This might be associated with late spring cold coming from the soil surface as the bottom and outer part of the tree was more suffered from the disease.

• Preliminary study on micro area based spatial distribution of Monilinia fructigena in an organic apple orchard

  19-21.

  I. J. Holb

  A. Rózsa

  F. Abonyi

  Views:

  629

  In this study, we aimed to report a preliminary study on micro area based spatial distribution of Monilinia fructigena in an organic apple orchard. Results showed that number of symptomatic fruit ranged between 22 and 42 in 2013 and between 25 and 35 in 2014. Number of asymptomatic fruit ranged between 111 and 187 in 2013 and between 119 and 167 in 2014. Disease incidence of fruit ranged between 19.7 and 23.2% in 2013 and between 19.1 and 26.5% in 2014. Disease aggregation index ranged between 0.111 and 0.335 in 2013 and between 123 and 401 in 2014. Three of the four trees showed significant within canopy aggregation of disease for fruit brown rot symptoms in both years. However, the remaining one tree exhibited random patterns during both years. Disease aggregation indicated a disease spread by fruit-to-fruit contact and/or an aggregated
  pattern of insect damage.

• The salt tolerance of vegetable paprika varieties

  39-45.

  K. Slezák

  I. Terbe

  N. Kappel

  K. Tóth

  Views:

  459

  In our experiments, we have chiefly tested the salt sensitivity of sweet pepper varieties. In cold forcing, 0.3 1/plant nutrient solutions of different NaCI content were given twice weekly. EC of the nutrient solutions containing 0.25% Volldünger Linz complex fertilizer was made up to 6, 10, 14 and 18 mS/cm, respectively, by 2.51/9.17/17.97/26.76 g/m² doses of pharmacopeal NaCI every week. The solution used for the control treatment contained Volldünger only (EC 4.4 mS/cm). Irrigation was made with pure water (EC 0.6 mS/cm) when necessary.

  The varieties chosen for the experiments were the following: Feherözön, HRF F₁, Syn. Cecei (of white, conical fruit), Boni (of white, blunt, infolded fruit), Titan F₁ (of pointed, hot fruit) and Pritavit F₁ (of tomato shaped fruit).

  In general, the symptoms caused by NaCI treatments (with doses higher than 10 g/m² weekly) have been the following:

  • They have reduced the leaf area, the height of the plants, the total and the early yield, the number of fruit set per square meter, the average weight of the fruit (and, in some measure, fruit length, too) and the thousand seed weight.
  • They have increased the calcium and the chlorine content of the leaves and fruits and the dry matter content of the fruits.
  • They haven't affected the dry matter content of the leaves, the nitrogen, phosphorus and potassium content of the leaves and fruits, and the germinating ability of the seed.
  • The effect on stem diameter and on seed production per fruit has been contradictory in some cases.

  The effects of the intermediate treatments haven't been explicit in several cases.

  The results of the examination of cuticular secretion have indicated the increase of the sodium and chlorine content of the leaves. This can be important in field growing where the rainwater may wash out a part of sodium and chlorine from paprika leaves.

  The hot, pointed variety and the tomato shaped paprika haven't shown clearly higher salt tolerance than the varieties of white fruit colour.

• Incidence of virus fungal diseases on three stone fruits cultivars in Hungary

  107-109.

  I. J. Holb

  M. Soltész

  J. Nyéki

  Z. Szabó

  Views:

  1337

  In this two-year study, incidence of Polystigma rubrum on plum, and Apiognomonia erytrostoma on apricot were evaluated on several stone fruit cultivars in Hungary. Results showed that most apricot cultivars expressed symptoms caused by A. erytrostoma, graded between 2 and 3 (10-50%) by the end of the summer in 2005 and 2006. The most tolerant apricot cultivars were Budapest and Mandulakajszi while the most susceptible ones were ’Magyar kajszi’ and ’Piroska’.Assessments made on plum showed that most of the plum cultivars were tolerant or lowly susceptible to P. rubrum such as ’Ageni’, ’Althann ringló’, ’Bluefre’, ’Cacanska najbolja’, ’Silvia’, ’Ruth Gerstetter’, ’Tuleu gras’ and ’Utility’. The most susceptible plum cultivars to P. rubrum were ’Besztercei clones’ and ’Debreceni Muskotály’.

• Effect of postharvest sodium benzoate treatment on some fruit parameters of two organic apple cultivars

  35-37.

  B. Molnár

  Sz. Szabó

  Á. Veres

  I. J. Holb

  Views:

  1072

  The aim of this study was to investigate the effect of postharvest sodium-benzoate treatment on some fruit parameters of two organic apple cultivars (’Topaz’ and ’Florina’). Assessments were made at three times during storage: 17 November 2019, 20 December 2019 and 23 January, 2020. During every assessment dates, each fruit was observed separately, and determined the proportion of i) healthy fruits (%), ii) post-harvest fruit rot diseases iii) fruits with mechanical injury (%), iv) fruit with russetting (%), v) damage of codling moth and vi) Ca-deficiency symptoms. In addition, fruit weight (g) was measured at each assessment date. Sodium benzoate reduced the fruit decay and the proportion of healthy fruit was higher in this treatment compared to water treated fruit. This effect could be seen in all assessment dates and on both cultivars. Effects on other parameters were various according to cultivar and assessment dates. Loss of fruit weight was similar in both treatments and cultivars compared to control treatment.

• Growth and productivity of plum cultivars on various rootstocks in intensive orchard

  77-81.

  L. Magyar

  K. Hrotkó

  Views:

  565

  Trees of three plum cultivars (Stanley, Cacanska Lepotica and Althann's Gage) were planted at Szigetcsép experimental station in Spring 1994 and trained to slender spindle with the aim to test their growth, effect of productivity under not irrigated conditions and to evaluate the adaptability of rootstock/scion combinations to intensive orchards. As control, trees on Myrobalan C 162/A (P. cerasifera) seedling are planted. In the trial two rootstocks are from Slovakia: Myrobalan MY-KL-A (red leaf) and Myrobalan MY-BO-1, vegetatively propageted. Further on two French rootstocks, the Marianna GF 8-1: Marianna plum (P. cerasifera x P munsoniana) and the Sainte Julien GF 655/2 (P. insititia) were involved. The Hungarian bred plum Fehér besztercei (P. domestica), which is recommended as apricot rootstock is also tested. Rootstocks MY-BO-1 and Fehér besztercei were planted with cultivar Stanley only. Trees were planted to a spacing of 5x3 m trained to slender spindle with 3-4 permanent basal branches. After yield start (1997) trees have been pruned only in summer, after harvest. In the alleyway the natural plant vegetation is mown, the orchard is not irrigated.

  Based on tree size, vigorous rootstocks are Marianna GF 8-1 and Myrobalan C 162/A seedling, medium vigorous are MY-BO-I and MY­KL-A; vegetative propageted myrobalan plums from Slovakia, while St. Julien GF 655/2 and Feller Besztercei proved to be growth reducing rootstocks. No significant difference between the rootstocks was found in turning to bearing. Under non-irrigated condition at Szigetcsép, cultivar Stanley produced the highest yield per area unit on vigorous rootstock (GF 8-1). The cultivar Althann's Gage produced the highest yield efficiency on Marianna GF 8-1 and they were healthy in the last 10 years. The symptoms of Althann's Gage trees on MY-KL-A rootstock indicate a possible incompatibility. The average fruit weight was significantly influenced by crop load on cultivar Cacanska lepotica, while no statistically proved differences were found on Stanley and Althann's Gage. The Cacanska lepotica trees produced significantly lower yield and larger fruit weight on St. Julien GF 655/2 rootstock. Adaptability to spindle training system depends on vigour of scion/rootstock combination: low or medium vigour cultivars (C. lepotica, Stanley) are good choice for spindle training systems even on vigorous rootstock; while the St. Julien GF 655/2 can be recommended only for vigorous Althann's Gage under our soil and climate conditions.

• Virus and virus-like diseases of grapevine in Hungary

  25-36.

  J. Lázár

  Gy. D. Bisztray

  Views:

  509

  Viruses and viroids are submicroscopic infectious particles which can cause disease symptoms on grapevine. These parasites are depending completely on the energy metabolism of the plant cell. To enter the host cell plant viruses depend on injuries or on transmission via invertebrates (insects, nematodes, etc.). Viruses are classified by many characters including particle morphology, host range and information content of the genome. At present about 70 viruses including 7 viroids infecting grapevine are known. In single or mixed infections they are potentially detrimental to the quality and quantity of grape production in any growing area of the world. Some viruses can cause severe economic damage in vineyards. In Hungary many important viruses and viroids have been detected in grape. This review summarises characteristics of viruses and the results of detection and characterization of virus and virus like diseases of grapevine in Hungary. The identification of the causal agent, its transmission, geographical distribution and the development of the diagnostic methods are also discussed.

• Disease progress of apple scab caused by Venturia inaequalis in environmentally friendly growing systems

  56-62.

  I. J. Holb

  Views:

  617

  Progression of apple scab epidemic in six apple cultivars, including two current and susceptible (Gala Must, Elstar), two old (Egri Piros, Darusóvári), and two resistant cultivars (Relinda, Releika), were described and analysed in a two-year-study, in two environmental-friendly growing systems (organic and integrated). Curves of disease progress, linear regression analysis of transformed disease incidence data and Area Under Disease Progress Curves (AUDPC) were used to characterise the epidemic processes of the selected cultivars. Cumulative disease progress curves showed continuous but asymmetrical scab development on the moderate or highly susceptible cultivars Gala Must, Elstar and Egri Piros, and on the tolerant or resistant cultivar Darusóvári and Relinda, in both systems. The cultivar Releika showed no symptoms either on fruit or leaf. In linear regression analysis, the best linearisation was given by logistic transformation. Adequate parameters leaf disease incidence rate, of obtained from a regression equation, were higher in the organic system than in the integrated system. Values of AUDPC showed great differences in leaf disease incidences among cultivars and between growing systems. AUDPC gave more differences for comparison of progresses of disease epidemic than growth rate of disease in different systems of disease control. Moreover, the obtained results were compared with similar studies on different pathosystems, and biological interpretations of the analyses are discussed below.

• Comparison of Xanthomonas arboricola pv. juglandis isolates from walnut trees grown in Romania and Hungary

  65-69.

  A. Bandi

  Views:

  482

  Among diseases that affect walnut, bacterial blight is considered the most important one in all walnut growing areas both from Hungary and Romania. For the determination of susceptibility/resistance of walnut cultivars in our posterior work planned, 61 bacterial isolates were collected from walnuts showing symptoms of blight, with the purpose of isolating Xanthomonas arboricola pv. juglandis (Xaj). The characteristic Xaj colonies, frequently present as saprophytes in the infected plant tissues, were separated from other bacteria according to their morphology, yellow colour, hydrolysis of starch, and oxidation of glucose. All isolates were tested for pathogenicity by hypersensitive reaction on tobacco leaves (Nicotiana tabacum L.), bean pods (Phaseolus vulgaris L) and unripe nuts (Juglans regia L.). Determination of taxonomy of the selected isolates denotes a possible subdivision (races, biotypes) of Xaj occurring in different geographical areas, API 20NE and API 50CH kits were used. Hungarian and Romanian strains showed a high degree of similarity of carbohydrate utilization but slightly differed from the type strain. All were Cu-sensitive.

• Reactions of different plant organs of pear cultivars to Erwinia amylovora infection

  17-21.

  K. Honty

  Z. Boldog

  M. Göndör

  J. Papp

  K. Kása

  M. Hevesi

  Views:

  359

  Research project has been initiated in 1999 with the aim of evaluating the degree of susceptibility/resistance of pear cultivars grown in Hungary to fire blight disease caused by Erwinia amylovora. The recently selected promising cultivars were also examined. Inoculation experiments were conducted in controlled greenhouse conditions because of quarantine regulations in Hungary. Following the disease process, development of symptoms of plant organs (shoots, flower parts, fruits) was observed. Suspension of two E. amylovora strains (Ea 21, Ea 23) isolated from pear was used in a mixture (5x10⁸ cells x m1^-1) for the inoculation. Twenty-six pear cultivars were examined and grouped into four categories: low susceptibility, moderately susceptible, susceptible and very susceptible. Most of the cultivars were susceptible or very susceptible while some promising 'Eldorado', 'Harrow Delight' and `Hosui' showed low susceptibility.

• Comparative study of different fertile groups in plums

  71-76.

  D. Surányi

  Views:

  393

  The plum traditional fruit species in Hungary, several local cultivars was born in the different grower's districts. The author that investigated, that are morphological differences between an odds find self-fertile, self sterile (with functional stamens) and male sterile plum cultivars. For it thought about main questions of a scientific debate sown up and the study this way gave reactions totalize. There were in three fertile groups 8-8 type of feature plum cultivars in periods of 1992-2001, respectively 1993-1999. It was founded by author big odds found the troops on the basis of 9 traits between. Pistil length of self sterile cultivars very typical, such as sesquipedalian flower peduncle of the self-fertile plums and the hypoandry of male sterile cultivars. The relative stamen number and the pollen viability as well significant odds gave.

  The average fruit mass and sharka infection of self-fertile plums this troops extreme work. According to cultivar's averages the shark symptoms standard the right correlation the singular traits, but those one part of her with each other not shown connection.

  The annuity potencies underdeveloped the troops behind and the troops within cultivar's differences had case significance. The results usable the male sterile cultivars and progeny further its investments.

• The importance of clonal selection of grapevine and the role of selected clones in production of healthy propagating stocks

  15-24.

  E. Hajdu

  N. Korac

  P. Cindric

  D. Ivanisevic

  M. Medic

  Views:

  668

  Genetical alterations and phytosanitary status promote the variability and modify the appearance of vine. Old vine varieties in old vineyards are highly variable and well adapted to selection. Clonal selektion is based on a visual performance: valuable individuals (clones) are picked out according to visible symptoms or characters. The genetical stability of clones is proved by testing the vegetatively propagated progenies on the basis of morphological and molekular (SSR, AFLP, SMPL, RAPD) markes. Authors take great care of the visual phytosanitary selection as part of the clonal selection being the oreliminary step to develop pathogen-free propagation stocks. In Serbia (Vojvodina) the selection breeding has been carried on for several decades resulted in comparative clone trials with home and imported clones of Welsch Riesling, Chardonnay, Pinot gris, White Riesling. Among the clones of home selection SK.54 Welsch Riesling clone is the most valuable. Its clearing from pathogene is being carried on in an interregional IPA programme (HUSRB/0901/214/123) in Kecskemét. In Kecskemét, the centre of the Hungarian Danube vine region 5 vine clones have been registered (Cegléd szépe K.73, Irsai Olivér K.11, Kövidinka K.8, Hárslevelû K.9, Pannónia kincse K.56). Besides them 18 virus-tested clones have also been qualified.Works aiming at their complete exemption are going on in order to obtain clones free of propagation wood-borne diseases.

• Investigation on the transmission of some Tobamoviruses by pollen and seed in pepper (Capsicum annuum L.)

  127-131.

  P. Salamon

  M. Kaszta

  Views:

  411

  Five pepper cultivars were mechanically inoculated with isolates of three Tobamovirus species, viz. the "Gelb" strain of tobacco mosaic virus (TMV-G), the XM-isolate of dulcamara yellow fleck virus (DYFV-XM) and the Nov/H isolate of pepper mild mottle virus (PMMV-Nov/H), respectively. Symptoms caused by the viruses were characterised. The viruses were sucessfully re-isolated from different organs (roots, leaves, fruit parts) of susceptible peppers to test plants. It was estabilished, that the pollen of diseased peppers carried infective virions at least on their surface. Washes of seeds were highly infective, but no infectivity was found after treatment of the seeds with 2% NaOH or 10% Na3PO4. No infectivity of inocula prepared from seed-coats of alkaline treated seeds was established. Infection of young seedlings grown from untreated seeds was demonstrated, while the seedlings came from alkaline treated seeds remained free of infective virus. The possible role of pollen and seed in the epidemiology of Tobamoviruses pathogenic to pepper as well as the importance of seed treatment is discussed.