scholarly journals Potential of Propane Flamers for Reduction of Apple Scab Primary Inoculum on Orchard Ground

HortScience ◽  
1997 ◽  
Vol 32 (2) ◽  
pp. 267-270 ◽  
Author(s):  
H. Desilets ◽  
S. Rochefort ◽  
J. Coulombe ◽  
S. Yelle ◽  
J. Brodeur
Keyword(s):  
Venturia Inaequalis ◽  
Apple Scab ◽  
Treatment Strategies ◽  
Residual Effect ◽  
Ground Cover ◽  
Ground Level ◽  
Thermal Reduction ◽  
Apple Orchard ◽  
Primary Inoculum ◽  
Testing Facility

The potential impact of propane flamers on the development and release of ascosporic inoculum of Venturia inaequalis (Cke.) Wint. from infected dead apple (Malus domestica Borkh.) leaves that overwintered on the soil of an experimental orchard was assessed. Thermal reduction of scab primary inoculum was first conducted under controlled conditions using an indoor testing facility. At the time of ascospore maturation, heavily infected leaves were submitted to temperature rises ranging from 150 to 200 °C with open-flame burners, thus reducing the number of ascospores subsequently released by 76% and 87%, respectively. During Spring 1995, thermal treatments of overwintered dead leaves were performed directly on the ground of an apple orchard with an experimental propane flamer design to generate uniform heat at ground level. Four thermal treatment strategies, involving two dates of flaming and two heat intensities, were tested. Flaming orchard ground, when performed in early May, before significant development of ground cover, reduced the number of ascopores released from infected dead leaves by half. A significant residual effect of the treatments on ascospore ejection was still observed 2 and 4 weeks after the treatments, thus indicating that ascospore maturation inside the leaves may be reduced by heat treatment. These results indicate potential for propane flamers to reduce apple scab primary inoculum in orchards.

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

2013 ◽  
Vol 19 (3-4) ◽  
Author(s):  
I. J. Holb ◽  
A. Rózsa ◽  
F. Abonyi
Keyword(s):  
Primary Infection ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
Apple Orchard ◽  
Scale Level ◽  
Scale Evaluation ◽  
Farm Scale ◽  
Apple Cultivars ◽  
Apple Production ◽  
Fallen Leaves

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.

scholarly journals Organic apple growing using sanitation treatments against apple scab

2007 ◽  
Vol 13 (1) ◽  
Author(s):  
F. Abonyi ◽  
I. J. Holb
Keyword(s):  
Untreated Control ◽  
Primary Infection ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
Apple Orchard ◽  
Apple Cultivar ◽  
Lime Sulphur ◽  
Fallen Leaves

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).

scholarly journals Spread apple scab in the western region of Ukraine

2016 ◽  
pp. 232-238
Author(s):  
A. Skoreyko
Keyword(s):  
Venturia Inaequalis ◽  
Apple Scab ◽  
Apple Orchard ◽  
Western Region ◽  
Pathogen Destruction ◽  
The Western Region

The results of the survey to identify apple orchard pathogen destruction Venturia inaequalis in Chernivtsi and Zakarpattia regions. Minimum scab lesions observed in the Chernovtsy region Khotyn district (Farm «Mayak») on the varieties Golden, Glory winner, Idared.

scholarly journals Comparative Study of Dutch and Hungarian Environmentally-friendly Apple Orchards on Potential Ascospore Dose of Apple Scab

2002 ◽  
pp. 31-36
Author(s):  
Imre Holb ◽  
Bart Heijne
Keyword(s):  
Apple Scab ◽  
Environmentally Friendly ◽  
Apple Orchard ◽  
Bud Break ◽  
Apple Orchards ◽  
Primary Inoculum ◽  
Medium Level ◽  
Very High ◽  
Epidemic Risk ◽  
Organic Orchards

In a 2-year study, Dutch and Hungarian environmentally-friendly apple orchards were compared as regards the amount of apple scab primary inoculum. The PAD (potential ascospore dose) method was used to quantify the potential amount of primary inoculum (ascospores) per m2 orchard floor. Applying this method, the number of lesions per m2 of leaf in the autumn (LD), the proportion of the orchard floor covered by leaf litter at bud break (LLD) and potential ascospore dose (PAD) were determined. In autumn, LD values ranged between 2.2 and 13.5 in the integrated orchards, while in the organic orchards the values were between 42.5 and 106.2, with especially high values in the Dutch organic orchard. LLD values ranged between 24 and 43% at bud break in both countries. PAD values were 10-60 times higher than those of the integrated orchards. The PAD values were between 673 and 4275 ascospore/m2 orchard floor in the integrated orchards, while in the organic orchards these values were 37102 and 52390 ascospore/m2 orchard floor, respectively. On the basis of the recorded primary inoculum quantity, the Dutch integrated apple orchard is considered to be excellently protected, while the Hungarian orchard has a medium level of protection. However, both countries’ organic orchards can be regarded overall as being very poorly protected. Accordingly, in the integrated orchards the predicted epidemic risk is low or medium, while in the organic orchards it is very high on the basis of PAD values.

scholarly journals Breakdown of the Scab Resistance Gene Vf in Apple Leads to a Founder Effect in Populations of the Fungal Pathogen Venturia inaequalis

2004 ◽  
Vol 94 (4) ◽  
pp. 364-369 ◽  
Author(s):  
Fabien Guérin ◽  
Bruno Le Cam
Keyword(s):  
Resistance Gene ◽  
Founder Effect ◽  
Allelic Variation ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
Apple Orchard ◽  
Scab Resistance ◽  
Vf Gene ◽  
Major Resistance Gene ◽  
High Level

The recent breakdown of Vf, a major resistance gene to apple scab, provided an opportunity to analyze a population genetic process within the matching virulent subpopulation of the fungus Venturia inaequalis. We utilized the amplified fragment length polymorphism technique and allelic variation at four microsatellite loci to assess genetic structure of 133 isolates of V. inaequalis from a single commercial apple orchard sampled from one cultivar carrying the Vf gene (Judeline) and three cultivars devoid of the Vf gene. Both analyses indicated a strong decrease of the genetic diversity among isolates from the Vf cultivar compared with the high level of diversity among isolates from the three other cultivars. This leads to a high genetic differentiation between virVf and avrVf groups (FST > 0.17). Analyses of the genetic distance between AFLP patterns based on the Jaccard index indicate that all virVf isolates could be assigned to a single clonal lineage. These results lead us to conclude that the clonal structure of the population isolated from the Vf cultivar is an example of a founder effect in response to a resistance gene breakdown and it is likely that this event occurred in the orchard during the sampling year.

scholarly journals An Assessment of Organic Apple Production in Kentucky

2015 ◽  
Vol 25 (2) ◽  
pp. 154-161 ◽  
Author(s):  
Mark A. Williams ◽  
John G. Strang ◽  
Ricardo T. Bessin ◽  
Derek Law ◽  
Delia Scott ◽  
...  
Keyword(s):  
Insect Pests ◽  
Venturia Inaequalis ◽  
Cydia Pomonella ◽  
Total Yield ◽  
Apple Scab ◽  
Codling Moth ◽  
Apple Orchard ◽  
Lower Limbs ◽  
Organic System ◽  
Apple Production

Although the interest in and production acreage of organic fruit and vegetables has grown in recent years, there are questions about the viability of perennial crops such as apple (Malus ×domestica) in an organic system in Kentucky because of the long, hot, and humid growing season. Thus, the objective of this project was to assess the severity of the challenges to organic apple production in Kentucky. A high-density, organic apple orchard was established in 2007 in the University of Kentucky Horticultural Research Farm in Lexington. The orchard of apple scab (Venturia inaequalis)–resistant ‘Redfree’, ‘Crimson Crisp’, and ‘Enterprise’ trees on ‘Budagovsky 9’ (B.9) rootstock, trained in a vertical axis system, was managed using organically certified techniques and materials for disease and insect control since its inception. Tree growth, tree and fruit injury from insect pests and diseases, and yield over the period 2011–13 were studied. Periodic, shallow cultivation kept the ground beneath the trees free of vegetation once the lower limbs were pulled up and away from the path of the equipment. Vole (Microtus sp.) damage was a continuing problem despite the use of trunk guards and cultivation to remove habitat around the trees. Total fruit yield ranged from 1.2 to 8.1 kg/tree across years and cultivars, with the marketable proportion of the total yield averaging 68% for Redfree and 43% for Crimson Crisp and Enterprise over the 3-year period. The unmarketable fruit exhibited a high incidence of plum curculio (Conotrachelus nenuphar) damage, with generally less damage from codling moth (Cydia pomonella) and sooty blotch (Glosodes pomigena)/flyspeck (Schizathyrium pomi). In addition, in two of the three seasons, ‘Crimson Crisp’ and ‘Enterprise’, which were harvested at later calendar dates then ‘Redfree’, had significant levels of powdery mildew (Podosphaera leucotricha) injury, ‘Enterprise’ had significantly greater bitter rot (Glomerella cingulata), and ‘Crimson Crisp’ showed fruit and foliar damage from cedar apple rust (Gymnosporangium juniperi-virginianae). Because ‘Redfree’ was the only cultivar with an acceptable marketable proportion of the fruit crop, the use of early ripening disease-resistant apple cultivars may have the greatest potential for successful organic apple production in Kentucky and the surrounding region.

scholarly journals The Effect of Different Forms of Sulphur on Incidence of Apple Scab on Apple Tree (Malus x domestica Borkh) Gloster CV.

2019 ◽  
Vol 26 (1) ◽  
pp. 199-208
Author(s):  
Hana Bělíková ◽  
Martin Mészáros ◽  
Ladislav Varga ◽  
Július Árvay ◽  
Barbara Wiśniowska-Kielian ◽  
...  
Keyword(s):  
Foliar Application ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
Apple Orchard ◽  
The Other ◽  
North East ◽  
Infection Pressure ◽  
Scab Control ◽  
High Infection ◽  
The Individual

Abstract From 2014 to 2015 the influence of foliar application of sulphur on apple trees (Gloster cv.)was investigated in the apple orchard at the Research and Breeding Institute of Pomology in Holovousy (North-East Bohemia, Czech Republic). The experiment was based on foliar applications of fertilizers containing different forms of sulphur: elemental S0, sulphate SO42− and thiosulphate S2O32− (in combination with other macro- and microelements) and fungicides with or without sulphur: Kumulus (S0 + F) and the conventional fungicide programme (F), in the respective treatments. Apple scab incidence on leaves and fruits was investigated in each experimental year according to the relevant methodology of the OEPP/EPPO standard PP1/5(3) Venturia inaequalis. Data on the incidence of apple scab correlate with the process of pathogen life cycle and risk of infection on the given dates. The incidence of apple scab was the lowest in 2014 in treatment S0 + F (10.8 % on leaves, 2.8 % on fruits) and F (15.8 % on leaves, 6 % on fruits) where conventional fungicides were used. When compared with the other treatments these treatments were the most effective even if the incidence of scab in the individual treatments in 2015 increased by 28 to 60 % due to high infection pressure. The results confirmed the efficiency of the conventional fungicide programme (S0 + F and F) against apple scab incidence on fruits. What is more, the results were slightly better in the treatment, where the conventional fungicide programme was combined with fertilizer containing elemental S (S0 + F) in comparison with fungicides applied alone (F). The effect of the other forms of sulphur (SO4 and S2O3) on apple scab control has not been confirmed. According to the results, the application of the conventional fungicide programme (S0 + F and F) is more effective against scab incidence than the inorganic forms of sulphur alone.

EXPERIMENTAL DATA ON CHEMICAL CONTROL OF MAIN PATHOGENS AND PESTS IN AN APPLE ORCHARD IN NORTHEASTERN ROMANIA IN 2019

2020 ◽  
Vol 13 ◽  
pp. 105-109
Author(s):  
Cristina Ionela Turcu ◽  
Agurița Aftudor Manolache ◽  
Ionel Perju ◽  
Simona Mihaela Chelaru ◽  
Margareta Corneanu
Keyword(s):  
Venturia Inaequalis ◽  
Cydia Pomonella ◽  
Apple Scab ◽  
Apple Orchard ◽  
Climatic Conditions ◽  
Research Station ◽  
Pest Species ◽  
North Eastern ◽  
Golden Delicious ◽  
Fruit Growing

"The researches were carried out in 2019 in an apple plantation with Jonathan, Golden Delicious, Starkrimson varieties grafted on MM106 in the fields of the Fălticeni Development Centre belonging to the Development Research Station for Fruit Growing Iași (North Eastern Romania). The climatic conditions in 2019 were favorable for the development of pathogens Venturia inaequalis, Podosphaera leucotricha and Monilinia fructigena. In the conditions of fungicide treatments, the varieties sensitive to apple scab on fruits were Starkrimson and Golden Delicious with an attack degree between 4.5 and 10.5%. Pest species Cydia pomonella and Adoxophyes reticulana showed a frequency of attack of 45% and 15%, respectively in the case of untreated control. The results of the studies highlight the importance of applying phytosanitary treatments correlated with climatic conditions and resistance of varieties to the attack of diseases and pests."

scholarly journals Spatial Distribution of Venturia inaequalis Airborne Ascospores in Orchards

2002 ◽  
Vol 92 (7) ◽  
pp. 769-779 ◽  
Author(s):  
J. Charest ◽  
M. Dewdney ◽  
T. Paulitz ◽  
V. Philion ◽  
O. Carisse
Keyword(s):  
Spatial Distribution ◽  
Negative Binomial Distribution ◽  
Binomial Distribution ◽  
Negative Binomial ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
Apple Orchard ◽  
Economic Losses ◽  
Frequency Distributions ◽  
Rain Events

Apple scab (Venturia inaequalis) causes important economic losses in many apple production areas of the world. The disease is controlled by numerous fungicide applications regardless of the presence of ascospores in the orchard. Airborne ascospore concentration (AAC) can be measured in real time to time fungicide applications. However, the level of heterogeneity of the AAC in commercial orchards was unknown. Consequently, the spatial distribution of V. inaequalis ascospores was studied in a commercial apple orchard of 0.43 ha. The potential ascospore dose (PAD) and AAC were measured in 40 quadrats each of 108 m2. In each quadrat, the AAC was monitored during the major rain events in spring 1999 and 2000 using spore samplers. The variance-to-mean ratio for the PAD and for most of the AAC sampling dates was >1, indicating an aggregated pattern of distribution. None of the frequency distributions of the most important ascospore ejection events followed the Poisson probability distribution, indicating that the pattern of distribution was not random. For all events, AAC had an aggregated pattern of distribution as suggested by the negative binomial distribution. The PAD followed neither the Poisson nor the negative binomial distribution. Geostatistical analyses confirmed the aggregated pattern of distribution. The cultivars had an effect on the PAD and AAC distribution pattern, but both PAD and AAC were not uniformly distributed within a block of the same cultivar. Therefore, the number, location, and height of samplers required to estimate AAC in orchards need to be investigated before using information on AAC for decision making.

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