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Strategies for regulation of black rot (Guignardia bidwellii) in organic viticulture
Project
Project code: 2804OE032
Contract period: 01.10.2005
- 31.01.2010
Budget: 645,493 Euro
Purpose of research: Applied research
Black rot has evolved to a widespread disease in some vine growing areas in Germany where it can cause severe damage. A joint research project has been initiated with the objective to collect basic data on the biology of the disease in the newly affected areas, and to develop management strategies with respect to the specific conditions in organic viticulture. The biology of Guignardia bidwellii and its interactions with the grapevine host was investigated with respect to the development of fruiting bodies and spores as well as the process of leaf-infection. Together with weather data and information on grape phenology these data can be used to assess infection pressure and to develop decision support tools. The specific sensitivity of traditional and 'disease tolerant' grapevine cultivars was assessed both in the greenhouse and in the field. While all traditional varieties where highly susceptible, some of the 'disease tolerant' cultivars exhibited a lower or a very low susceptibility to black rot. Infected canes and tendrils proved to be significant sources of inoculum for primary infections of grapevine leaves. Infestation of clusters and economic damage could be reduced when infected leaves were removed from the canopy. The efficiency of a wide range of bacteria, fungi, fungicides and so called 'plant strengtheners' was evaluated by tests in-vitro and on potted vines in the greenhouse. Effective compounds were further tested in field experiments under practical conditions. The combination of wettable sulphur with copper-hydroxide proved to be the most effective treatment, which was comparable to the efficiency of an organic fungicide. The quantity of copper applied over the season could be considerably reduced by replacing copper with stone meal in periods of low infection pressure. Plant extracts containing saponin were highly effective against black rot under greenhouse conditions. Probably due to their insufficient rainfastness, the saponins were not sufficiently effective under field conditions. Nevertheless, the saponins appear to be promising compounds to control black rot if an adequate formulation could be achieved.
The results of this research project provide the necessary information for winegrowers to set up a comprehensive management concept for black rot in organic viticulture.
Section overview
Subjects
- Crop Protection
- Viticulture
- Organic Farming
Framework programme
Funding programme
Excutive institution
Institute for Plant Protection in Fruit Crops and Viticulture - Fruit Cops (JKI-OW)