Borgen, Anders (2000) Hvedens stinkbrand - en udfordring for principperne for økologisk jordbrug. Thesis, Den Kongelige Veterinær- og Landbohøjskole , Institut for Jordbrugsvidenskab. Anders Borgen.
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Document available online at: http://www.agrologica.dk/publikationer/Ph.D.-afhandling.pdf
Summary
I afhandlingen beskrives principperne for økologisk plantebeskyttelse og der argumenteres for, at en plantesygdom som stinkbrand primært bør forebygges frem for at blive bekæmpet i et økologisk dyrkningssystem. Stinkbrandens biologi analyseres med henblik på at finde mulige forebyggende dyrkningsmetoder. Endvidere undersøges mulige bekæmpelsesmetoder, som er tilpasset økologisk jordbrug. Det konkluderes, at der findes forebyggende metoder, og at det er sandsynligt, at en systematisk udnyttelse af disse vil kunne forhindre hovedparten af problemerne med sygdommen. Det konkluderes endvidere, at der er muligheder for bekæmpelse i økologisk jordbrug, som kan bruges som sikkerhedsnet under dyrkningssystemet.
I afhandlingen gengives 6 eksperimentelle artikler, som dækker udvalgte emner inden for stinkbrandens biologi og bekæmpelse. Det vises, at stinkbranden kan agere som jordbåren patogen også i dyrkningssystemer med flere års dyrkning af ikke modtagelige afgrøder. Det dokumenteres, at mejetærskeren kan fungere som spredningsvektor for sporer, og at der i de første 3-4 tømninger af en mejetærskers korntank efter høst af en angreben mark er risiko for at overføre sporer til en efterfølgende afgrøde. Det vises, at stinkbrand kan bekæmpes fuldstændig ved neddypning i varmt vand i 1-5 minutter ved 50-55ºC uden påviselig negativ påvirkning af kornets spiring. Patogenet er mest følsom over for temperaturen, mens kornet er mere følsom over for tiden ved den pågældende temperatur. Stinkbrand kan bekæmpes ved coatning med mælkepulver, dog ikke uden negativ effekt på kornets spiringshastighed. Den negative effekt på spiringen er proportional med doseringen af mælkepulver, medens effekten på patogenet er størst med lav dosering. Herved er der en høj selektivitet ved lave doseringer, der kan udnyttes i kombination ved andre metoder. Det vises at nogle biologiske midler har en effekt, men at der ikke p.t. er kommercielt tilgængelige biologiske midler, der alene kan bekæmpe sygdommen effektivt. Ved at kombinere behandling med mælkepulver og biologiske midler forbedres mulighederne for at udvikle et biologisk middel til bekæmpelse af stinkbrand. Det vises, at man i de fleste hvedesorter kan gennemføre eksperimentelt arbejde med stinkbrand ved at basere diagnosen på bladsymptomer i stedet for akssymptomer, hvilket kan nedsætte tidsforbruget f.eks. ved eksperimentelt arbejde med udvikling af bekæmpelsesmetoder.
Summary translation
The thesis starts with discussion of the principles of organic agriculture, and it is argued that a plant disease like common bunt should be prevented rather than be treated in an organic cropping system. The biology of the pathogen is analysed in order to find preventive measures for crop infection and some treatments applicable in organic farming. I conclude that preventive methods are available, and that these will be able to prevent most problems with the disease. However, treatments applicable in organic farming are available that can be used to secure the cropping system in cases where preventive measures fail to do so.
In the thesis 6 articles are reprinted, covering selected issues of the biology and control of common bunt. I show that common bunt can act as a soil-borne disease in cropping systems with several years without susceptible crops. It is shown that the combine harvester can serve as a transmission vector for the pathogen, and that the risk of spore transmission to a non-infected crop is present for up to 4 emptyings of the seed tank, if the combiner has harvested an infected crop. It is shown that common bunt can be effectively controlled by dipping the seeds in hot water for 1-5 minutes at 50-55ºC without a significant reduction in seed germination. The pathogen is more sensitive to the temperature level, while seed germination is more sensitive to the duration of the treatment. Coating seeds with milk powder has an effect on bunt infection, but with this treatment seed germination is significantly reduced. This reduction in germination is proportional to the milk powder dose applied, while the effect on disease development is most pronounced at low doses. Therefore the selectivity of the treatment is highest at low doses meaning that it can be used in combination with other treatment. It is shown that some other biological treatments have effects, but at the moment in Denmark no such commercial seed treatment agents are available with an adequate effect. By combining milk powder and biological agents, the chance for development of an effective treatment is improved. Finally, it is shown that leaf symptoms of bunt infection can be used in many wheat varieties instead of diagnosis in the head of the plant, and that this method can decrease the time used in experimental work such as the development of new seed treatments.
| EPrint Type: | Thesis |
|---|---|
| Thesis Type: | Ph.D. |
| Keywords: | Frøbårne sygdomme, stinkbrand, Tilletia caries tritici |
| Subjects: | Crop husbandry > Crop health, quality, protection Crop husbandry > Breeding, genetics and propagation Crop husbandry > Production systems > Cereals, pulses and oilseeds |
| Research affiliation: | Denmark > Other organizations |
| Deposited By: | Borgen, Ph.D. Anders |
| ID Code: | 263 |
| Deposited On: | 25 Aug 2003 |
| Last Modified: | 12 Apr 2010 07:27 |
| Document Language: | Danish/Dansk |
| Status: | Published |
| Refereed: | Not peer-reviewed |
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