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ntegrating the latest research findings into an overall concept for the regulation of downy mildew on onions in ecological farming: varieties, cultivation practices and prospects of use of biocontrol agents
Project
Project code: 2806OE073
Contract period: 01.04.2007
- 30.09.2010
Budget: 207,319 Euro
Purpose of research: Applied research
Downy mildew, caused by the pathogen Peronospora destructor, is the most important Laubkrankheit in onion cultivation. It regularly - weather permitting - to serious yield and quality losses. In recent years, both in organic as well as in integrated onion crop progress in the control of the pathogen with regard to varietal resistance, methods of cultivation and prospects of use of pesticides has been made. The goal of this project is to examine the individual actions in small parcels and on practice areas and integrate them into an overall concept for the control of downy mildew on onions. The results will make a practical contribution to the practice to improve crop safety and quality of organic onions, to meet the increasing demand for food and processing industry of onions grown organically through intensification of cultivation and surface extension to. The following specific measures are examined: (1) new onion varieties with proven resistance to downy mildew in comparison with best standard varieties, (2) the methods of cultivation 'direct seeding' and 'onion seed (culture on early seedlings)' with selected resistant and standard varieties, (3) the direct control of downy mildew by new biologics in the light of the forecast model ZWIPERO the timing of drug application. Work will be performed in conjunction with the project `06OE034 integrating the latest research findings on a comprehensive approach to the regulation of downy mildew on onions in organic farming: variety selection and cultivation practices' of organic farming Excellence of Lower Saxony (ABLE) in Visselhövede. The findings from the joint operation will be continuously at work, at seminars and field days and presented in publications in magazines and the Internet to ensure a direct and rapid transfer into practice.
Results:
Downy mildew, caused by Peronospora destructor is the main foliar disease in onions. In organic onion production, no effective control measures are available. This project is part of a joint venture with the Kompetenzzentrum Ökolandbau Niedersachsen (KÖN) in Visselhövede (project 06OE034). The following control measures were tested: (1) four new onion varieties (Yankee, Hylander, Hystand und Santero) with proven resistance against downy mildew, (2) the cropping systems ''directly seeded '' and ''transplants’ (seven plants / pot) with the varieties Yankee and Santero as well as Summit, (3) plant extracts of sage and liquorice as well as the microbial agent Aneurinibacillus migulanus for the direct control of downy mildew (in cooperation with the Julius Kühn-Institute in Darmstadt, Germany). During the field trials 2007 – 2009, the highly resistant varieties were free of downy mildew except so called ‚off types’, single heavily diseased plants. In 2007 and 2008, marketable yield of susceptible varieties was only slightly reduced in comparison to highly resistant varieties due to low infection pressure. In 2009, however, high infection pressure caused serious yield losses in all susceptible varieties. Comparing the cropping systems, the effect of year and variety was predominant over the system effect. The plant extracts of sage and liquorice and the microbial agent were highly effective in reducing downy mildew of onions under controlled conditions. At low disease pressure or using a medium susceptible variety, efficacy of the biological agents reached more than 70%. Extracts of liquorice and preliminary experimental formulations of the extract (Trifolio-M, Lahnau, Germany) showed very little rain fastness under semi-field conditions. However, in a field trial in 2010 using drop leg techniques and a timed application of an experimental formulation of liquorice a reduction in disease incidence and severity was observed.
Section overview
Subjects
- Crop Protection
Framework programme
Federal Organic Farming Scheme and other forms of sustainable agriculture (BÖLN)
