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Apple scab (Venturia inaequalis) and pests in organic orchards

Sandskär, Boel (2003). Apple scab (Venturia inaequalis) and pests in organic orchards. Diss. (sammanfattning/summary) Alnarp : Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae. Agraria, 1401-6249 ; 378
ISBN 91-576-6416-1
[Doctoral thesis]

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Domestication of apples goes back several thousand years in time and archaeological findings of dried apples from Östergötland in Sweden have been dated to ca 2 500 B.C. Worldwide, apples are considered an attractive and healthy fruit to eat. Organic production of apples is increasing abroad but is still at very low levels in Sweden. This study deals with major disease and pest problems in organic growing of apples. It concentrates on the most severe disease, the apple scab (Venturia inaequalis). Resistance to apple scab was evaluated during three years in over 450 old and new apple cultivars at Alnarp and Balsgård in southern Sweden. There were significant differences between the cultivars and years. About ten per cent of the cultivars had a high level of resistance against apple scab. The correlation between foliar and fruit scab was stronger when the scab infection pressure was high (1998-1999), compared to when it was low (2000). Polygenic resistance is a desirable trait since such resistance is more difficult to overcome by the pathogen. A common denominator for polygenic resistance among the cultivars assessed was 'Worcester Pearmain'. The leaf infection of apple scab was compared at three locations: Alnarp, Kivik and Rånna (Skövde) in an observation trial for 22 new apple cultivars. The ranking of the cultivars was similar at the three locations. The best cultivars, 'McShay' and 'Sansa', are unfortunately not suitable for growing in Sweden, due to climatic conditions. However, several other cultivars might be useful in organic growing. The incidence of apple scab races was investigated for the first time in Sweden. Races 1-4 and 6 were reported from different geographical locations in Sweden (1999-2001), and tested in growth chamber/greenhouse trials. Race 1 was present at all sites and race 7 was reported on Malus floribunda 821 for the first time in a field trial at Kivik in 2002. Apple scab lesions were also found on the ornamental species Malus baccata jackii. In an experimental organic orchard with 'Amorosa' and 'Discovery' interplanted with ornamental shrubs, the insect and spider fauna was investigated. Codling moth was considered to be a key pest in the orchard. Winter moth and apple sawfly damaged the fruit to a significantly higher extent in 'Discovery' than 'Amorosa'.

Authors/Creators:Sandskär, Boel
Title:Apple scab (Venturia inaequalis) and pests in organic orchards
Series Name/Journal:Acta Universitatis Agriculturae Sueciae. Agraria
Year of publishing :February 2003
Number of Pages:39
ALLI. Sandskär, B. & Gustafsson, M. 2002. Susceptibility of twenty-two apple cultivars to apple scab in Sweden, J Plant Diseases and Protection 109(4), 338-349. II. Sandskär, B. & Gustafsson, M. 2003. Classification of apple scab resistance in two assortment orchards. Genetic Resources and Crop Evolution, In press. III. Sandskär, B. Abundance of spiders, beneficial insects and pests in an organic apple orchard. Submitted. IV. Sandskär, B. & Liljeroth, E. Incidence of apple scab races in Sweden. Manuscript. V. Sandskär, B. 2002. Apple scab infection in three differently managed orchards. Organic production of Fruit and Berries. NJF Meeting, Oct 22. Web-publishing.
Place of Publication:Alnarp
Associated Programs and Other Stakeholders:Z - SLU - Library > Odla mera
ISBN for printed version:91-576-6416-1
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:H Protection of plants and stored products > H20 Plant diseases
F Plant production > F08 Cropping patterns and systems
Subjects:Not in use, please see Agris categories
Agrovoc terms:malus, apples, venturia inaequalis, scabs, orchards, organic gardening, fruit crops, disease resistance, mixed cropping, beneficial organisms, sweden
Keywords:Apple cultivars, apple scab races, resistance biology, rosy apple aphid, sanitation practices, interplanting
Permanent URL:
ID Code:162
Department:(NL, NJ) > Institutionen för växtvetenskap
Deposited By: Boel Sandskär
Deposited On:17 Feb 2003 00:00
Metadata Last Modified:22 Mar 2015 15:10

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