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

2003 ◽  
Vol 9 (3-4) ◽  
Author(s):  
I. J. Holb
Keyword(s):  
Relative Humidity ◽  
Growth Rates ◽  
Production Systems ◽  
Disease Incidence ◽  
Apple Scab ◽  
Organic Production ◽  
Regression Analyses ◽  
Integrated Production ◽  
Disease Progress ◽  
Weather Parameters

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.

scholarly journals The effect of reduced sprinkler programs on the main fungal pathogens of apple in environmentally sound production systems

2010 ◽  
pp. 13-16
Author(s):  
Barbara Balla ◽  
Mónika Fazekas ◽  
Péter Lakatos ◽  
Ferenc Abonyi ◽  
Imre Holb
Keyword(s):  
Fungal Pathogens ◽  
Sound Production ◽  
Production Systems ◽  
Disease Incidence ◽  
Apple Scab ◽  
Brown Rot ◽  
Organic Production ◽  
Point Of View ◽  
Integrated Production ◽  
Serious Disease

Aim of our two-year study was to evaluate the possibilities of chemical use against key fungal pathogens (apple scab, apple powdery mildew and brown rot) in integrated and organic apple production. Therefore, first, disease incidence was compared in standard and reduced spray programmes and then each technological variation was evaluated from practical point of view. Altogether four spray programmes were compared. Standard and reduced spray programmes were performed in the integrated production. The same pesticides were used in the reduced sprayprogramme compared to standard one but numbers of spray were reduced by 25% at the second half of the season. Standard and reduced spray programmes were also performed in the organic production and the numbers of spray were reduced by 40% in the reduced spray programme. Incidence of diseases was low in both standard and reduced spray programmes in integrated production. Diseases level was high in the organic production and disease increased significantly in the reduced spray programmes compared to standard programmes. Results showed that reduction in spray numbers at the second half of the season can be used practically in integrated production. Omission of sprays in organicproduction resulted in serious disease management risk; therefore, it is not recommended for practical use. 

scholarly journals Effect of Production System and Pruning on Temporal Development of Cercospora depazeoides and on Berry Yield in Black Elderberry Orchards

Plant Disease ◽  
2009 ◽  
Vol 93 (6) ◽  
pp. 625-631 ◽  
Author(s):  
I. J. Holb ◽  
J. M. Gáll ◽  
B. Fodor
Keyword(s):  
Leaf Spot ◽  
Production Systems ◽  
Disease Incidence ◽  
Organic Production ◽  
Integrated System ◽  
Disease Development ◽  
Temporal Development ◽  
Cercospora Leaf Spot ◽  
Organic System ◽  
Disease Progress

In a 2-year study, the temporal development of Cercospora leaf spot (Cercospora depazeoides) and berry yield were evaluated in two production systems (integrated and organic) and in two winter pruning treatments (trees pruned to four and eight scaffolds) in two black elderberry (Sambucus nigra) orchards in Hungary. Under organic production, leaf spot onset occurred 2 to 4 weeks earlier (mid- and late July) in both years and both orchards compared with the integrated program. Disease then continuously progressed until the final assessment date (late September) in both years, reaching a maximum final disease incidence of 15.9% in the integrated system and of 38.2% in the organic system. In general, disease progress after late August was greater on trees pruned to eight scaffolds than on trees pruned to four scaffolds in both production systems. Both final disease incidence and area under the disease progress curves (AUDPC) were significantly lower (P < 0.001) in the integrated treatments compared with organic ones. Across all treatments, both disease measures were significantly (P < 0.05) lower on trees pruned to four scaffolds compared with trees pruned to eight scaffolds. However, when the effect of pruning on final disease incidence and AUDPC was analyzed separately for integrated and organic systems, pruning caused uniformly significant differences in disease development only for the organic system. Berry yield was significantly higher (P < 0.05) in the integrated system compared with the organic system, but pruning showed no significant effect on yield. Overall, pruning to four scaffolds resulted in consistently lower disease development in organic production compared to integrated. Thus, winter pruning may be useful as a Cercospora leaf spot management practice in organic elderberry orchards.

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

2005 ◽  
Vol 11 (1) ◽  
Author(s):  
I. J. Holb
Keyword(s):  
Powdery Mildew ◽  
Production System ◽  
Production Systems ◽  
Venturia Inaequalis ◽  
Disease Incidence ◽  
Apple Scab ◽  
Organic Production ◽  
Environmentally Benign ◽  
Apple Cultivars ◽  
Apple Production

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.

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

2009 ◽  
Vol 15 (4) ◽  
Author(s):  
I. J. Holb ◽  
M. Fazekas ◽  
F. Abonyi ◽  
P. Lakatos ◽  
S. Thurzó ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Production Systems ◽  
Apple Scab ◽  
Codling Moth ◽  
Fruit Production ◽  
Organic Production ◽  
Integrated Production ◽  
Growth Capacity ◽  
Apple Production

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.,

scholarly journals Analysis of Summer Epidemic Progress of Apple Scab at Different Apple Production Systems in the Netherlands and Hungary

2005 ◽  
Vol 95 (9) ◽  
pp. 1001-1020 ◽  
Author(s):  
I. J. Holb ◽  
B. Heijne ◽  
J. C. M. Withagen ◽  
J. M. Gáll ◽  
M. J. Jeger
Keyword(s):  
Factor Analysis ◽  
The Netherlands ◽  
Inflection Point ◽  
Production Systems ◽  
Disease Incidence ◽  
Relative Rate ◽  
Apple Scab ◽  
Disease Progress ◽  
Progress Curve ◽  
Apple Production

Two, 4-year studies on summer epidemic progress of apple scab were conducted at Randwijk, the Netherlands, from 1998 until 2001 and at Eperjeske, Hungary, from 2000 until 2003. Disease assessments were made on scab-susceptible cv. Jonagold. A range of nonlinear growth functions were fitted to a total of 96 disease progress curves (3 treatment classes × 2 plant parts × 2 disease measures × 4 years × 2 locations) of apple scab incidence and severity. The three-parameter logistic model gave the most consistent fit across three treatment classes in the experiment (integrated, organic-sprayed, and organic-unsprayed). Parameters estimated or calculated from the three-parameter logistic function were used to analyze disease progress. These were disease incidence and severity on the day of the first assessment (Ys); final disease incidence or upper asymptote for incidence (Yif) or severity (Ysf); fruit incidence and severity on day 40, after which no new lesions on fruits appeared (Y40); leaf incidence and severity on day 75, at which shoot growth stopped (Y 75); relative (β) and “absolute” (θ) rates of disease progress; inflection point (M); and area under the disease progress curve (AUDPCS) standardized by the duration of the total epidemic. Comparisons among disease progress curves were made by correlation and factor analysis followed by Varimax rotation. There were large differences but high positive correlations among the parameters Ys, Yf, θ, and AUDPCS across the three treatment classes. In the factor analysis, two factors accounted for more than 85% of the total variance for both incidence and severity. Factor 1 gave an overall description of epidemic progress of both scab incidence and severity and included the parameters Yf, Y40, Y75, θ, and AUDPCS. Factor 2 identified a relationship between the relative rate parameter (β) and the inflection point (M) for severity and a relationship between disease incidence and severity. For an integrated or an organic orchard, θ, AUDPCS, and one of Yf or Y75 (because of the link with host phenology) can characterize apple scab epidemics during summer. Based on these findings, improved scab management approaches were provided for integrated and organic apple production systems.

scholarly journals Effect of Compost Amendments on Disease Severity and Yield of Tomato in Conventional and Organic Production Systems

Plant Disease ◽  
2002 ◽  
Vol 86 (2) ◽  
pp. 156-161 ◽  
Author(s):  
P. A. Abbasi ◽  
J. Al-Dahmani ◽  
F. Sahin ◽  
H. A. J. Hoitink ◽  
S. A. Miller
Keyword(s):  
Disease Severity ◽  
Production Systems ◽  
Disease Incidence ◽  
Organic Production ◽  
Fruit Rot ◽  
High Rate ◽  
Bacterial Spot ◽  
Marketable Yield ◽  
Tomato Production ◽  
Compost Amendments

Field trials were conducted over 2 years to assess the effects of compost amendments on disease development in organic and conventional processing tomato (Lycopersicon esculentum L.) production systems. The incidence of anthracnose fruit rot was reduced in organic tomato plots amended with a high rate of composted cannery wastes compared with the incidence in nonamended control plots in 1998 when disease incidence was high. Marketable yield was increased by 33% in compost-amended organic plots. Plots amended with a high compost rate had more ripe fruit than the nonamended control. The incidence of anthracnose and of total disease on fruit was less on the cultivar OH 8245 than on Peto 696. Total fruit yield of OH 8245 but not Peto 696 in organic plots was increased by amendment with composted cannery wastes. In conventional tomato production, composted yard wastes increased disease severity on foliage both years but reduced bacterial spot incidence on fruit in 1997, when disease pressure was high. The incidence of anthracnose was not affected by composted yard wastes. Marketable and total fruit yields of Peto 696 were not increased in compost-amended conventional plots. The plant activator Actigard reduced foliar disease severity and the incidence of bacterial spot and anthracnose on fruit, while increasing yield of marketable fruit.

scholarly journals Branching features of apple cultivars in integrated and organic production technology

2018 ◽  
Vol 24 (3-4) ◽  
Author(s):  
P. Dremák ◽  
Á. Csihon ◽  
I. Gonda
Keyword(s):  
Organic Farming ◽  
Production Technology ◽  
Production System ◽  
Production Systems ◽  
Environmentally Friendly ◽  
Organic Production ◽  
Integrated System ◽  
Integrated Production ◽  
Apple Cultivars ◽  
Environmentally Friendly Production

In our study, vegetative characteristics of 39 apple cultivars were evaluated in environmentally friendly production systems. Numbers of the branches of the central leader in different high zones were shown. According to our results, number of the branches of the axis was probably larger in the integrated production system, compared to the organic one, which is related to the conditional status of the trees. Based on our experiences training and maintaining canopies in integrated system was easier, as relative more extensive canopies were needed in organic farming.

scholarly journals Assessing Consumer Preferences of Scab-resistant Apples: A Sensory Evaluation

2010 ◽  
Vol 20 (5) ◽  
pp. 885-891 ◽  
Author(s):  
Kathleen Kelley ◽  
Jeffrey Hyde ◽  
James Travis ◽  
Robert Crassweller
Keyword(s):  
Sensory Evaluation ◽  
Production Systems ◽  
Consumer Preferences ◽  
Apple Scab ◽  
Organic Production ◽  
Initial Assessment ◽  
State University ◽  
Pennsylvania State University ◽  
Apple Cultivars ◽  
Hedonic Scale

One hundred forty-nine consumers participated in a sensory evaluation, conducted on 14 Nov. 2008, at The Pennsylvania State University, University Park, PA, to determine consumer acceptance and perceptions of scab-resistant apples (Malus ×domestica). Consumers were exclusively screened for liking and eating apples. The study provides tree fruit growers and marketers in the mid-Atlantic United States with information on consumer preferences for apples that might substitute for common cultivars that require frequent apple scab pesticide applications. Resistant cultivars are also attractive in organic production systems. During the 10-minute sensory evaluation, panelists rated five scab-resistant apples [‘Crimson Crisp’, ‘GoldRush’, NY 75907–49 (NY 49), ‘Crimson Topaz’, and ‘Sundance’] and a commercially available non-resistant cultivar, Jonagold, on appearance, aroma, texture, flavor, and overall liking using a nine-point hedonic scale (9 = “like extremely” and 1 = “dislike extremely”). Three of the four apples tested with a red peel (‘Crimson Topaz’, NY 49, and ‘Crimson Crisp’) were rated significantly higher than the other apples on the basis of appearance, receiving mean ratings that were between “like moderately” and “like very much,” a rating of 7 and 8, respectively. In regards to texture, ‘Crimson Topaz’ and ‘Crimson Crisp’ were significantly higher than ‘Jonagold’ and NY 49, with mean ratings between “like slightly” and “like moderately.” For overall liking scores, ‘Crimson Crisp’, which was rated between “like slightly” and “like moderately,” was not significantly different from ‘Crimson Topaz’ and ‘GoldRush’; however, ‘Crimson Crisp’ was rated higher than ‘Jonagold’, NY 49, and ‘Sundance’. Panelists also responded to questions regarding their food-purchasing attitudes and behaviors. Sixty-two percent of panelists purchased fresh apples for themselves and/or other household members at least “two or three times a month” during an average year. Only 2.7% responded that they purchased fresh apples “more than once a week.” This study of consumer preferences provides an initial assessment of the feasibility of marketing new apple cultivars and organic apples within the mid-Atlantic U.S. region. Those that performed well in the sensory evaluation should be candidates for additional market research.

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

2000 ◽  
Vol 6 (4) ◽  
Author(s):  
I. J. Holb
Keyword(s):  
Regression Analysis ◽  
Linear Regression ◽  
Venturia Inaequalis ◽  
Disease Incidence ◽  
Linear Regression Analysis ◽  
Apple Scab ◽  
Integrated System ◽  
Organic System ◽  
Disease Progress ◽  
Leaf Disease

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.

scholarly journals Rate of scab infection and quality parameters of apple fruit in organic and integrated production systems

2000 ◽  
Vol 6 (4) ◽  
Author(s):  
I. Gonda ◽  
I. J. Holb ◽  
K. Bitskey
Keyword(s):  
Leaf Area ◽  
Production Systems ◽  
Apple Scab ◽  
Weather Conditions ◽  
Specific Weight ◽  
Fruit Production ◽  
Quality Parameters ◽  
Organic Production ◽  
Integrated System ◽  
Environmental Systems

In this study, the rate of scab infection and quality parameters (content of vitamin-C, dry matter, sugar, total acids, specific weight, quality index and flesh firmness) of some apple cultivars are given, moreover, the relation between those characters was examined in two environmental systems (organic and integrated) in a rainy season. In the organic fruit production, scab infection of leaves was significantly higher than in the integrated system, in case of the same cultivars, which means that the rate of decrease in leaf area was heavier in the organic production. Cultivars did not differ statistically in parameters of inner content when the integrated system was compared to the organic one. Results did not show statistical difference between loss of leaf area caused by apple scab and the parameters of inner content, which is attributed to the regeneration of leaf area due to favourable weather conditions. Data on apple scab and inner content of the fruit justify essentially the environmental systems of apple production.  

Sign in / Sign up

Export Citation Format

Share Document