Alternative fungicides to control apple scab in organic apple production: results of an orchard trial in 2003

Apple scab, caused by the fungus Venturia inaequalis, is the disease that most often decreases yield and causes loss of fruit quality in organic apple production. Damage to the fruits consists of brown to black spots, but in some years and on some varieties attacks can result in small misshapen fruits, that are totally unsuitable for fresh consumption

Prospecting for organic fungicides and resistance inducers to control scab (Venturia inaequalis) in organic apple production

As a part of the REPCO project we are prospecting for plant extracts and other materials to control apple scab in order to find substitutes for copper fungicides in organic apple production. Two routine screening systems are used to evaluate the potential of materials to control apple scab; one testing the effect of materials on conidium germination on glass slides, and one testing the effect of materials on scab development on apple seedlings grown in growth chambers. Several interesting materials have been identified and a number have been selected for testing in experimental organic apple orchards. Studies of the mode of action of promising materials including induced resistance are on-going and work on improvement of timing and formulation is initiated at KVL

Organic field-testing of compounds to control apple scab (Venturia inaequalis) in combination with alleyway cover crops

To find new potential fungicides acceptable to organic production preventing apple scab (Venturia inaequalis) infections on leaf and fruits during primary apple scab infection period. The trials were carried out in combination with different cover crop treatments in single-tree plots. The formerly resistant variety ‘Delorina’ on rootstock M9, planted 1995 at a planting distance of 3.3 m x 1.6 m, unfertilized and with mechanical weed cleaning in the tree row, were used. The experimental orchard is located at Research Centre Aarslev (100 27´ E, 550 18´N)

New fungicides for apple scab control in organic growing

In the future control of apple scab in organic apple growing could be based on the use of natural fungicides like plant extracts and oils. Current projects are testing this idea

Alternativ bekæmpelse af æbleskurv i økologisk æbledyrkning

Æbleskurv forårsaget af svampen Venturia inaequalis er den skadevolder, som oftest forhindrer en god ydre kvalitet af æbler. Skurv er skyld i brune til sorte pletter på frugten og kan i nogle år og på nogle sorter angribe så kraftigt, at æblerne bliver meget små, misdannede og fuldstændig uegnede til spisning. Denne svampesygdom er årsag til en stor udbytte- og en meget stor kvalitetsnedgang i økologisk produktion

Contributions of EU-project REPCO to apple scab control

The objective of REPCO is to contribute to the replacement of copper fungicides in organic agriculture by new measures for control of downy mildew (Plasmopara viticola) in grapevine and scab (Venturia inaequalis) in apple. Both major European organic crops strongly depend on copper fungicides. Permitted amounts will be reduced stepwise during the following years (Council Regulation (EEC) 2092/91, Annex II) to avoid environmental risks. In European countries where copper fungicides are already out of use, production of organic apples suffers severe economical problems because of insufficient scab control. Potentiators of resistance, organically based fungicides and biocontrol agents are screened and evaluated in apple. Effects of crop management practices in organic agriculture on overwintering of Venturia inaequalis are assessed. Novel disease control measures and knowledge are integrated into organic management systems. 'Pipeline' products already under development elsewhere are included and where necessary optimised in their use

Control of apple scab by the use of the plants own defence mechanisms

One obvious possibility to control apple scab, caused by Venturia inaequalis, is to use the plant's inherent ability to defend itself by induced resistance. Preliminary experiments with induced resistance have been started in StopScab, a collaborative project between KVL and DIAS. The concept and use of induced resistance are brielfy described in the following

Bekæmpelse af æbleskurv ved brug af plantens egne forsvarsmekanismer

En oplagt mulighed for at bekæmpe æbleskurv, forårsaget af Venturia inaequalis, er at udnytte plantens egne evner til at forsvare sig gennem induceret resistens. Indledende forsøg med induceret resistens mod æbleskurv er sat i gang i projektet StopScab, som er et samarbejde mellem KVl og DJF. I artiklen beskrives kort hvad induceret resistens er, og hvad det kan anvendes til

Bekæmpelse af æbleskurv i økologisk frugtavl - kan planteekstrakter, biologisk bekæmpelse og induceret resistens anvendes?

Der er et stort behov for at finde alternative muligheder til at bekæmpe æbleskurv i økologisk æbledyrkning, da de fleste tilgængelige metoder, inklusive sprøjtning med svovl, kun har ringe effekt. I det danske samarbejdsprojekt "StopScab" mellem den Kgl. Veterinær- og Landbohøjskole og Danmarks JordbrugsForskning undersøges planteekstrakter, essentielle olier, biologiske bekæmpelsesorganismer og midler, der aktiverer plantens egne resistensmekanismer (induceret resistens) for deres effektivitet mod æbleskurv

Orchard testing of new, alternative fungicides against apple scab

Apple scab, caused by the fungus Venturia inaequalis, is the disease that most often decreases yield and causes loss of fruit quality in organic apple production. Damage to the fruits consists of brown to black spots, but in some years and on some varieties attacks can result in small misshapen fruits, that are totally unsuitable for fresh consumption