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• Epidemiology of brown rot on two apple cultivars in an organic apple orchard

  49-52.

  I. J. Holb

  J. Gáll

  Views:

  164

  In a two-year-study, the temporal development of brown rot (Monilinia fructigena) on fruits was analysed in an organic apple orchard on an early (Prima) and one late (Idared) maturing cultivars at Debrecen-Józsa in Hungary. Out of five mathematical functions (linear, exponential, three-parameter logistic, Gompertz, Bertalanffy-Mitscherlich), the three-parameter logistic function gave the best fit to brown rot incidence of all cultivars in both years. Disease progress started at the end of June for cv. Prima and at the end of July for cv. Idared, then disease increased continuously from 6-8 weeks up to harvest in all cultivars. Descriptive disease variates derived from the three-parameter logistic function were used to analyse disease progress. These were: Yf, the final disease incidence; Y55, fruit incidence at day 55; Y95, fruit incidence at day 95; b and q, the relative and the absolute rate of disease progress, respectively; T1.5, the time when disease incidence reaches 1.5 %; M, the inflection point and AUDPC, area under disease progress curve. Descriptive disease variates were significantly different (P<0.05) for cv. Prima compared to cv. Idared, except for the relative and absolute rate of disease increase, b and q, respectively. The largest differences among cultivars were in the values of the AUDPC. Disease progress curves and descriptive disease variates were presented and the practical implications of the results were discussed.

• Incidence of two leaf fungal diseases in two plum training systems

  15-17.

  B. Molnár

  M. Varga

  A. Vámos

  I. J. Holb

  Views:

  415

  In a two-year study, we aimed to determine the susceptibility of four plum cultivars to two fungal pathogens of plum (Stigmina carpophila and Polystigma rubrum) in two training systems with tree spacings of 4 x 1.5m and 6 x 3m. Results showed that shothole symptoms were not detected on cvs ’Bluefre’ and ’Stanley’ in August, 2016. Disease incidence was above 50% in the case of ’Čačanska lepotica’ in both training systems in 2016. There were no significant difference between the two training systems. Shot hole incidence was lower in the 6 x 3m spacings compared to the 4 x 1.5m spacings on cv ’President’ in 2016. Cultivar ’Čačanska lepotica’ showed the highest incidence of Stigmina carpophila in the 4 x 1.5m spacing in 2017. Disease incidence of Stigmina carpophila was significantly lower in the 6 x 3m spacing compared to the 4 x 1.5m spacing. Shothole incidences on cv ’President’ were similar to the values in 2016 ranging from 40% to 60%. Leaf disease incidence was higher in the 4 x 1.5m spacing compared to the 6 x 3m plot. Low disease incidence (below 10%) was observed on cv ’Stanley’ in 2017 and only in the 4 x 1.5m spacing. There were no visible symptoms of blackhorn dotty in 2016 due to inadequate weather conditions for the Polystigma rubrum fungus. However, all the four cultivars were infected by Polystigma rubrum in 2017. The most susceptible cultivar was cv ’Čačanska lepotica’ with the highest disease incidence in the 4 x 1.5m spacing. Disease incidence of this cultivar was lower in the 6 x 3m spacing which was significantly less than in the 4 x 1.5m spacing. The least susceptible cultivar was ’Bluefre’ and symptoms were observed only in the spacing of 4 x 1.5m. The disease incidence of cv ’President’ was similarly low to cv ’Stanley’ in both spacings.

• Analyses of the pathogen and weather components of disease progress for modeling apple scab epidemics in integrated and organic production systems

  101-106.

  I. J. Holb

  Views:

  164

  The pathogen and weather components of apple scab disease progress were analysed in a three-year study, in two environmental-friendly production systems (organic and integrated) on cvs. `Idared', `Jonica' and 'Mutsu'. Linear regression analyses of transformed disease incidence and severity data and "area under the disease progress curves" (AUDPC) were used for the analysis of the pathogen component. To evaluate the role of the weather component in apple scab epidemic, first, the weekly disease increase was determined at a certain week (n). Weekly disease increase was related to rainfall, relative humidity, Mills' wetness period, temperature and interaction between temperature and relative humidity. Five different periods were used in the analyses: i) week (n-1), ii) week n(n-1), iii) week (n-2), iv) week (n-1)(n-2) and v) week n(n-1)(n-2). In the analyses of the pathogen component, the best transformation function was the logistic one. Regression analyses showed that disease growth rates were higher for disease incidence and for the organic production system than for disease severity and for the integrated production system, respectively. Disease growth rates for leaf incidence were higher than fruit incidence on all the three cultivars. AUDPC values showed great differences in both leaf and fruit incidences among cultivars and between the two production systems. The results the of analyses of the weather component showed that the best relationships between disease increase and weather parameters were found for fruit incidence and leaf incidence in week (n-2) in the organic and integrated production systems, respectively. Results also demonstrated that in week n(n-1) temperature played a more important role in the fungus development than the water parameters (relative humidity, rainfall and leaf wetness). Consequently, infection process is significantly dependent on almost all weather parameters, but during the incubation period the most important weather parameter is the temperature. Results were compared with similar studies and biological interpretations of the analyses are discussed.

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

  56-62.

  I. J. Holb

  Views:

  186

  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.

• The increasing importance of grapevine trunk diseases

  21-30.

  Cs. Kovács

  E. Sándor

  Views:

  309

  Grapevine trunk diseases (GTDs) are destroying the woody parts of the plants, resulting decline or dieback of the grapevine. More detailed research of the GTD began in 1950s, when Hewitt et al. (1957) observed that specific symptoms cannot be detected on the diseased trunks every year. Latest results have also proved that abiotic factors affect the appearance and the severity of the disease. Moreover several pathogenic fungi may play role as causative agents (Bertsch et al., 2013). Eutypa, Botryosphaeria, Phomopsis dieback, esca disease complex, and Petri disease are considered the major GTDs, where a variety of pathogens attack the woody perennial organs of the vine and ultimately lead to the death of the plant (Lehoczky, 1974; Larignon & Dubos, 1997; Rolshausen et al. 2010; Kotze et al., 2011; Bertsch et al., 2013; Fontaine et al., 2015).
  The GTD incidence has been reported to be increased during the last decades (Úrbez-Torres et al., 2014). The esca incidence has reached 60% to 80% in some old vineyards in southern Italy (Pollastro et al., 2000; Surico et al., 2000; Calzarano & Di Marco, 2007). The disease incidence of the esca was reported to be increased from 1.83% to almost 13%, between 2003 and 2007 in Hungary (Dula, 2011). There was detected a five times increase in the GTD disease incidence in the Tokaj Wine Region, Hungary between 2014 and 2016 (Bihari et al,
  2016).

• Cherry leaf spot incidence on 12 sweet cherry cultivars in integrated production

  65-67.

  A. Vámos

  I. J. Holb

  Views:

  208

  The aim of this study was to evaluate the cherry leaf spot (CLS) incidence on 12 sweet cherry cultivars in integrated sweet cherry production in three consecutive years from 2010 till 2012. Assessed cultivars (cvs.) were ’Aida’, ’Axel’, ’Biggareau burlat’, ’Blaze Star’, ’Celeste’, ’Germersdorfi 3’, ’Izabella’, ’Katalin’, ’Krupnoplodnaja’, ’Linda’, ’Sunburst’, ’Vera’Results showed that year had an essential effect on the CLS disease incidence. Cultivars showed great differences within years. Cultivar ’Celeste’ showed the lowest disease incidence on leaves in all years lower than 10%. The largest disease incidence on leaves was on cv. ’Sunburst’ in 2010, on cv. ’Germersdorfi 3’in 2011 and on cv. ’Axel’ in 2012. Disease incidence on these cultivars ranged between 10 and 25%.

• Some aspects of reduced disease management against Monilinia spp. in sour cherry production

  50-53.

  M. Fazekas

  F. Abonyi

  A. Madar

  P. Lakatos

  J. Gáll

  I. J. Holb

  Views:

  179

  The aim of this study was first to test the in vitro effeicacy of some fungicides against brown rot of sour cherry, and secondly to evaulate the effectiveness of reduced spray programmes against brown rot in integrated and organic sour cherry orchards. In vitro efficacy of 7 fungicides (Champion 50 WP, Kocide 2000, Nordox 75 WG, Olajos rézkén, Kumulus S, Rézkén, Rézoxiklorid) and another 6 fungicides (Score 25 EC, Efuzin 500 SC, Systane, Folicur Solo, Zato Plusz, Rovral) approved in organic and integrated production systems, respectively, were tested against brown rot of sour cherry. Altogether four spray programmes were performed i) standard integrated: sprays followed by forecasting systems during the season, ii) reduced integrated: sprays followed by forecasting systems but only 75% of the spray numbers used during the season-long spray programme, iii) standard oragnic: sprays applied every 7–14 days during the season and iv) reduced organic: 60% of the spray numbers used during the season-long spray programme. In vitro results showed that fungicides (with active ingredients of copper and sulphur) applied in organic production showed relatively high percent growth capacity of Monilinia fungus. Rézkén showed the highest and Kumilus S the lowest efficacy against brown rot. Fungicides applied in integrated production showed relatively low percent growth capacity of Monilinia fungus. Score 25 EC showed the highest and Rovral the lowest efficacy against brown rot. Field study showed that reduced spray programmes did not increase significantly brown rot incidence in the integrated field. However, brown rot incidence increased significanly (above 30%) in the reduced spray programme for the organic orchard.

• Effects of DMI and strobilurin fungicide combinations on scab and powdery mildew incidence in apple production: a preliminary study

  37-39.

  I. J. Holb

  M. Kocsis

  J. Kruppa

  F. Abonyi

  Views:

  214

  The aim of our study was to evaulate the effectiveness of four DMI and strobilurion fungicide combinations in a season-long disease management programme against apple scab and powdery mildew in two integrated apple orchards on cultivar Jonagold. The four spray programmes were: i) standard, ii) DMI dominant iii) strobilurin dominant, and iv) DMI and strobilurin dominant. Apple scab incidence as generally high in both orchards in the standard fungicide treatment plots ranged between 21.8 and 26.4%. Leaf scab incidence was higher in all treatments compared to fruit incidence. Scab incidence was generally higher at Mándok compared to Ófehértó. In both locations the lowest scab incidence was assessed in DMI dominant treatment ranged between 5 to 10.7%, which was not signifi cantly different from the DMI and strobilurin dominant treatment. Powdery mildew incidence was generally low in both orchards in all fungicide treatments ranged between 0.002 and 0.5%. Although there were no signifi cant differences among treatments, the lowest powdery mildew incidence was assessed in the DMI and strobilurin dominant treatment in Mándok and in the strobilurin dominant treatment in Ófehértó.

• Effect of reduced spray programmes on incidences of apple scab, powdery mildew and codling moth damage in environmentally freindly apple production systems

  75-78.

  I. J. Holb

  M. Fazekas

  F. Abonyi

  P. Lakatos

  S. Thurzó

  J. Nyéki

  Z. Szabó

  J. Kruppa

  B. Balla

  Views:

  665

  Still a large amount of pesticides and spary applications are used in environmentally friendly fruit production systems; therefore, the aim of our study was first to test the in vitro effeicacy of some fungicides against a key apple disease (apple scab), and secondly to evaulate the effectiveness of reduced spray programmes against apple scab, powdery mildew and coding moth in integrated and organic apple orchards. In vitro efficacy of 7 fungicides (Champion 50 WP, Kocide 2000, Nordox 75 WG, Olajos rézkén, Kumulus S, Rézkén, Rézoxiklorid) and another 6 fungicides (Score 25 EC, Efuzin 500 SC, Systane, Folicur Solo, Zato Plusz, Rovral) approved in organic and integrated production systems, respectively, were tested against apple scab. Altogether four spray programmes were performed i) standard integrated: sprays followed by forecasting systems during the season, ii) reduced integrated: sprays followed by forecasting systems but only 75% of the spray numbers used during the season-long spray programme, iii) standard oragnic: sprays applied every 7–14 days during the season and iv) reduced organic: 60% of the spray numbers used during the season-long spray programme. In vitro results showed that fungicides (with active ingredients of copper and sulphur) applied in organic production showed relatively high percent growth capacity of the apple scab fungus. Rézkén showed the highest and Kumilus S the lowest efficacy against apple scab. Fungicides applied in integrated production showed relatively low percent growth capacity of the apple scab fungus. Score 25 EC showed the highest and Rovral the lowest efficacy against apple scab. Field study showed that reduced spray programmes did not increase significantly scab incidence in the integrated field. However, scab incidence increased significanly (above 30%) in the reduced spray programme for the organic orchard.Mildew incidence was low (below 5%) in both integrated and organic spray programmes. Mildew incidence on both shoots and fruits increased significanly in the reduced spray programme for the organic orchard. Incidence of codling moth damage was affected the most by standard vs. reduced spray programmes. Though incidence remained below 10% in the integrated plots, the incidence was significantly higher in the reduced spray programme compared to the standard programme. Similar results were obtained for organic spary programmes, but the incidence was 10 times higher and the differences among the two programmes were larger.,

• 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:

  85

  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.

• Disease threshold for cherry leaf spot incidence on commercial sweet cherry cultivars

  52-54.

  M. Varga

  A. Vámos

  B. Molnár

  I. J. Holb

  Views:

  206

  The aim of this study was to demonstrate the 10% threshold level for cherry leaf spot incidence on 23 commercial sweet cherry cultivars in two training systems. Twenty three cherry cultivars were evaluated in the two training systems with a spacing of 4 x 1 m and with a spacing of 2 x 5 m. Results showed that leaves of many cultivars were heavily infected, e.g. cultivars (cvs) ’Biggareau Burlat’, ’Sunburst’, while others showed low disease incidence e.g. cvs ’Celeste’ and ’Blaze Star’. According to the 10 % threshold level, cv ’Celeste’ proved to be the most resistant cultivar to leaf infection, while cv ’Münchebergi korai’ exceeded extremely the 10% threshold level. Leaf spot incidence was affected by training system on most cultivars. Thirteen cultivars had less than 10% infection in the 4 x 1 m spacing (i.e. they did not reach the 10% disease threshold level). At the same time, only 3 cultivars showed less than 10% infection in the 5 x 2 m spacing.

• Analyses of temporal dynamics of brown rot development on fruit in organic apple production

  97-100.

  I. J. Holb

  Views:

  170

  In a two-year study, yield loss and temporal dynamics of brown rot development caused by Monilinia fructigena (Aderh. & Ruhl.) Honey were quantified and analysed in two organic apple orchards (Debrecen—Pallag and Debrecen—Józsa). The first infected fruits were observed at the beginning of August in both years and both locations, except for one occasion when the first infected fruit was found at the end of July. Temporal disease development was continuous up to harvest time in both years and locations. In the two years, pre-harvest yield loss on the trees amounted between 8.9% and 9.3% at Debrecen-Pallag and between 9.7% and 10.8% at Debrecen—Jozsa by fruit harvest. Incidence of infected fruits on the orchard floor ranged from 32.4% to 43.2% and from 53.3% to 61.9%, at Debrecen—Pallag and Debrecen—Józsa, respectively, by fruit harvest. Analyses of temporal disease progress showed that the best-fitted mathematical function was the power function in both orchards and years. Both parameters of the power function clearly demonstrated that incidence of brown rot on fruit increased faster on the orchard floor than on the tree. Moreover, the disease increase was faster at Debrecen—Józsa in most cases than at Debrecen—Pallag. Our results indicated that the strategy of disease management, the ripeness of the fruit and the presence of a wounding agent played an important role in the yield loss and in the temporal development of fruit disease incidence caused by M. fructigena in organic apple orchards. Biological and practical implications of the results are discussed.

• Effect of pruning on disease incidence of apple scab and powdery mildew in integrated and organic apple production

  57-61.

  I. J. Holb

  Views:

  230

  In a three-year study, the effect of two winter pruning treatments (strong and weak) on apple scab (Venturia inaequalis) and powdery mildew (Podosphaera leucotricha) was evaluated on six apple cultivars (`Rewena', `Elstar', 'Liberty', 'Gala', 'Pilot' and `Jonica') in two environmentally-benign apple production systems (integrated and organic). Results on apple scab showed that compared to the integrated production system, the pathogen caused significantly more infection on the leaves of cvs. `Elstar', 'Gala' and `Jonica' in the organic production system. The effect of pruning treatments on apple scab was mainly detectable on the cultivars susceptible to the disease such as cvs. 'Gala' and `Jonica'. The weak pruning correlated with a higher level of apple scab infection than the strong pruning, especially in the organic production system. Primary mildew infection was very low in both protection systems (below 2 %), therefore, effect of pruning on primary mildew infection could not be analysed. Low secondary mildew incidence was detected in the organically treated orchard part; however, incidence of powdery mildew was significantly higher (P> 0.05) on cvs. 'Elstar', 'Pilot' and `Jonica' in the integrated orchard part compared to cvs. 'Gala', 'Rewena' and 'Liberty'. The highest incidence of mildew was on cv. 'Elstar'. Pruning had very low effect on incidence of secondary mildew infection on leaves.

• Disease incidence of Monilinia fructigena coupled with codling moth damage and mechanical injury in an organic apple orchard

  55-57.

  I. J. Holb

  Views:

  210

  In a two-year-study, disease incidence of Monilinia fructigena were quatified and the importance of certain fruit wounding agents was determined. The first infected fruits were observed at the beginning of August in 2011 and 2012. Disease development was continuous until fruit harvest in both years. Pre-harvest yield loss caused by M. fructigena amounted on average 26.3% in 2011 and 40.4% in 2012 by fruit harvest. All infected fruits were injured mainly by mechanical injury factors and codling moth (Cydia pomonella). In this study, the most important wounding agents were codling moth and mechanical injury factors in organic apple orchards. In both years, our results showed that 65-75% of the infected fruits were damaged by codling moth in organic apple production. Moreover, 5-15% of the infected fruits were mechanically injured in the two years. Our results indicated that most of the damaged fruits fell on the orchard floor before harvest and they became an important secondary inoculum source of M. fructigena. Biological and practical implications of the results are discussed.

• 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:

  185

  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.

• Organic apple growing using sanitation treatments against apple scab

  11-13.

  F. Abonyi

  I. J. Holb

  Views:

  124

  Effects or sanitation practices were evaluated on primary and autumn infection by Venturia inaequalis in an organic apple orchard at Eperjeske on the moderately scab-susceptible apple cultivar Jonathan in 2005 and 2006. Evaluated sanitation practices were: i) collection of fallen leaves in autumn; ii) destroying fallen leaves by disc cultivation in autumn; iii) spraying fallen leaves with 2% lime sulphur in autumn; iv) spraying fallen leaves with 2% lime sulphur in autumn and then collection of fallen leaves in autumn; and v) untreated control. In both years, most sanitation practices reduced significantly (P< 0.05) scab incidence in the primary infection periods compared to untreated control. The highest leaf scab incidence was observed in the untreated plots (26:2 and 24.3% in 2005 and 2006, respectively), while the lowest was in the treatments of spraying fallen leaves with 2% lime sulphur combined with collection of fallen leaves (11.7 and 12.3% in 2005 and 2006, respectively).

• Role of organosilicone surfactant in apple scab control under scab conducive weather conditions

  23-25.

  I. J. Holb

  Views:

  173

  Fungicides of integrated fruit production (dithianon, captan, and diclofluanid) and an organosilicone surfactant were compared in spray schedules from green tip until summer in order to control apple scab caused by Venturia inaequalis and to evaluate their phytotoxicity on fruit. Sixteen sprays of 1.8 kg ha^-1captan, 0.41 ha^-1 dithianon, and 1.8 kg ha^-1 diclolfluanid significantly (P=0.05) reduced the incidence of leaf or fruit scab compared to unsprayed products. All fungicides applied with organosilicone at 0.1% resulted in lower incidence of scab on young and older leaves as well as on harvested fruit, but these were not statistically always better than fungicides applied alone. In case of diclofluanid, the fungicide applied with organosilicone at 0.1% resulted in significantly lower (P = 0.001) incidence of scab on young and older leaves. Diclofluanid applied with organosilicone at 0.1% gave the best scab control on leaf and fruit. Treatments applied with fungicides alone had no significant effect on plant phytotoxicity compared to untreated control. All fungicides applied with organosilicone at 0.1% increased (P = 0.05) fruit damage compared to untreated control or fungicide applied alone, though these were not always significantly different. In case of percentage of fruit russet, treatment of dithianon 0.4 1/ha + 0.1% organosilicone significantly increased fruit russet, while fruit russet index significantly increased in the treatment of diclofluanid 1.8 kg/ha + 0.1% organosilicone compared to untreated control. In sum, application of surfactants can help to increase efficacy of scab fungicides; and consequently, to reduce the risk of fungus infection under high scab disease pressure. This fact may also be helpful in fungicide resistance management and reduced-spray programs with accurate scab warning systems.

• Farm-scale evaluation of two widely used sanitation practices for reducing primary inoculums of apple scab in organic apple production

  15-18.

  I. J. Holb

  A. Rózsa

  F. Abonyi

  Views:

  176

  Effects of two widely used sanitation practices were evaluated at farm-scale level on leaf degradation and primary infection by Venturia inaequalis in an organic apple orchard (Eperjeske) on two apple cultivars (Jonathan and Prima) from 2011 to 2013. The tested sanitation practices were eradication of fallen leaves by collection and disc cultivation. Treatments of eradication of fallen leaves by collection and disc cultivation reduced signifi cantly (P< 0.001) leaf litter density with 70–85 and 40–55%, respectively, compared to untreated plots in both years. Above treatments in the same order reduced spring scab incidence with 40–50, and 10–20%, respectively, compared to untreated plots. Incidence of leaf scab in autumn was not signifi cantly lower (P< 0.05) in the treatments in the years.

• Some aspects of reduced disease management against Blumeriella jaapii in sour cherry production

  49-51.

  I. J. Holb

  A. Vámos

  P. Lakatos

  J. M. Gáll

  F. Abonyi

  Views:

  200

  The aim of this study was to evaluate the effectiveness of reduced spray programmes against cherry leaf spot in integrated and organic sour cherry orchards. Altogether four spray programmes were performed i) standard integrated: sprays followed by forecasting systems during the season, ii) reduced integrated: sprays followed by forecasting systems but only 75% of the spray numbers used during the season-long spray programme, iii) standard oragnic: sprays applied every 7–14 days during the season and iv) reduced organic: 60 % of the spray numbers used during the season-long spray programme. Our study showed that cherry leaf spot did not increase above 3.1, 7.4, and 8.9% in 2008, 2009, and 2010, respectively, in the integrated orchards. However, leaf spot incidence was above 20% in all years in the organic field. Reduced spray programme did not increase significantly cherry leaf spot incidence in the integrated field in either years. However, leaf spot incidence increased significanly (above 20%) in the reduced spray programme for the organic orchard.

• Micro area based spatial distribution of apple scab in an organic apple orchard

  21-23.

  I. J. Holb

  P. Lakatos

  F. Abonyi

  Views:

  200

  In this study, the objective was to report a two-year investigation on micro area based spatial distribution of apple scab in an organic apple orchard. Results showed that number of symptomatic plant part ranged between 587 and 623 on leaf and between 46 and 78 on fruit for an individual tree. Number of asymptomatic plant part ranged between 1034 and 1321 on leaf and between 119 and 193 on fruit. Disease incidence ranged between 35 and 40% on leaf and between 27 and 33% on fruit. Disease aggregation index ranged between 0.115 and 0.298 on leaf and between 0.117 and 0.221 on fruit. Three of the four trees showed significant within canopy aggregation of disease for leaf apple scab symptoms in both years. For fruit apple scab, two of the four trees showed significant random patterns in both years.

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

  35-37.

  I. J. Holb

  Views:

  180

  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.

• Experiments on the Resistance or Pepper Cultivars to Macrophomina phaseolina

  74-75.

  S. Kadlicskó

  J. Kovács

  J. Horváth

  G. Kazinczi

  Views:

  122

  The ashy stern blight of pepper (Capsicum annuum) is often caused by Macrophomina phaseolina. Serious wilt disease occurred between 1994 and 1996 of pepper plants in Hungary. In 1996-98 screening experiments were made on many pepper cultivars. Culture (Knopp) solution experiments, pot experiments, greenhouse and field trials were carried out. We determined the incidence of disease by visual examinations, testing on PDA culture, and light microscope. There were significant differences in susceptibility of cultivars and breeding materials.

   

• Ascospore dispersal of Venturia inaequalis and subsequent development of scab symptoms in a Hungarian organic apple orchard

  35-37.

  I. J. Holb

  Rózsa A.

  Abonyi F.

  Views:

  220

  In this study, we aimed to study ascospore dispersal of Venturia inaequalis and subsequent disease development in an organic apple orchard (Eperjeske) in 2012 and 2013 on apple cultiva ’Mutsu). Burkard spore trap in March and April were used to monitior ascospore concentration and number of scab symptoms were assesed 20 May in both years. Three peaks were detected in ascospore dispersal in the period of examination which was clearly related to the Mills infection periods. On the basis of the incubation period’s length in April (15–18 days), the appearance of first symptoms had direct connection with the peak of the ascospore discharge. The largest number of symptoms were observed on those parts of the orchards where where the inoculum sources were accumulated.

• Field trials with non-bactericide products to control fire blight in apple orchards

  55-60.

  T. Bubán

  P. Sallai

  J. Deme

  Views:

  132

  Recently, novel strategies and chemical agents for prophylactic protection against the bacterial (Erwinia amylovora) disease fire blight are being sought. Resistance-inducing compounds, such as prohexadione-Ca represent promising alternatives. Prohexadione-Ca is the active ingredient of the bioregulator Regalis, currently being introduced in several European countries and overseas. Another product used in this study was Biomit Plussz, a leaf fertiliser providing harmonic supply of nutrient elements, the complete supply is assumed to improve the tolerance against diseases.

  Treatments' effects of both of these products were compared to the effectiveness of treatments with antibiotics repeated twice, three or four times a season.

  In the years of 2001 and 2002, the effectiveness of both Regalis and Biomit Plussz in reduction of incidence of shoot blight was similar, or proved to be superior to the check treatments consisting of repeated sprayings of antibiotics. Last year (2003) treatments of streptomycin resulted — although within the same magnitude — in a somewhat better control of shoot blight than sprayings with the other compounds.

  As regards severity of blossom blight, inconsistent results were recorded concerning both Regalis and Biomit Plussz.

  In general, prohexadione-Ca is less efficient for controlling flower infection by E. amylovora as compared to shoot infections, since successful prophylactic treatments are difficult to carry out early in the season. The highest effectiveness in fire blight management can, therefore, be achieved by using prohexadione-Ca (as preventive protection) in combination with streptomycin or other suitable antibiotics (as curative protection).