Bundesprogramm Ökologischer Landbau: Pflanzenschutz in ökologisch wirtschaftenden Baumschulen der Bundesrepublik Deutschland

Plant protection in organic nursery production in the Federal Republic of Germany The project objective was to compile data on plant protection problems and control measures in organic production nurseries. The data was collected by surveys carried out with organic production nurseries and advisors. In 2003, 44 nurseries in Germany were run organically. 37 of them were certified according to the EC-Eco-Directive (Directive (EEC) No. 2092/91) which is equivalent to 1.1 % of all nurseries in Germany. All in all, only 15 advisors were found to advise organic nursery production on plant protection problems. The organic production nurseries were very heterogeneous in size and structure. Over two-thirds of the 31 enterprises were mixed-stock nurseries and offered a great variety of woody plants. Most nurseries were retailers, adjusting their supply to the demands of the local market. Nearly all nurserymen inspected their crops regularly for plant diseases, pests, and weeds. If plant protection problems arose, nurserymen consulted primarily technicalliterature or asked other nursery colleagues. Consultants were asked for help much less frequently. The occurrence of economically significant causes of damage varied very much from nursery to nursery. Most of the harmful organisms which were considered economically significant by nurseries only caused problems in individual nurseries. In existing stock, nurserymen controlled harmful organisms and undesired weed cover by various preventive and direct measures. However, more often than not, nurserymen did not indicate the success rate of their direct measures. Consultants mentioned successful control measures for some host-pest-combinations and some weeds in particular. Plant disease problems were a significant limiting factor for the variety of woody plants cultivated in organic nurseries. Nearly two-thirds of theinterviewed nursery managers had to remove sensitive species and varieties from their selection of woody plants - particularly orchard trees and ornamentals - due to phytopathogenic problems. Nurserymen would especially like to receive better support with marketing and plant protection problems from politicians and researchers. Practical proposals for focused studies are under discussion.