Inwendige ontsmetting van door Ascochyta pisi aangetaste erwtezaden met de antibiotica rimocidine en pimaricine, benevens enkele aspecten van het parasitisme van deze schimmel
One of the plant diseases, which is still difficult to control, is leaf, stem and pod spot of peas, caused by the fungus Ascochyta pisi. Seed disinfection is unsatisfactory, because the fungus may penetrate deep into the seed, beyond the reach of superficially active disinfectants. Therefore a search was made for disinfectants, penetrating the seeds, using ascochyta-infected seeds for tests. The most effective compounds were the newly discovered antibiotics rimocidin and pimaricin, products of Streptomyces spp. They penetrated the seeds and eliminated internal fungus without impairing germination. An 18-h soaking reduced the percentage of seeds with viable mycelium from 80 to less than 1 %. Dry or almost dry treatment was less effective. A further drawback of these antibiotics was the reversible loss of fungicidal activity inside plant tissue through adsorption, and inactivation by UV radiation.Rimocidin and pimaricin were nevertheless of interest because of their selectivity, being highly toxic to most fungi, but hardly toxic to bacteria and higher plants. Remarkable also was ready uptake by plants and seeds despite their large complex molecules.A new aspect of the parasitism of this fungus was that the fungus was often present in plant parts or whole plants without symptoms. Rarely the fungus was even isolated from seeds, harvested from plants without symptoms. It was also observed that during ripening of the pods many pycnidia appeared outside the limited brown-edged spots, typical for this disease.
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| Format: | Doctoral thesis biblioteca |
| Language: | Dutch |
| Published: |
Veenman
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| Subjects: | antigens, disinfection, fungicides, immunology, pezizomycotina, plant pathogenic fungi, plant protection, seed treatment, seeds, vicia, antigenen, desinfectie, fungiciden, gewasbescherming, immunologie, plantenziekteverwekkende schimmels, zaadbehandeling, zaden, |
| Online Access: | https://research.wur.nl/en/publications/inwendige-ontsmetting-van-door-ascochyta-pisi-aangetaste-erwtezad |
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| Summary: | One of the plant diseases, which is still difficult to control, is leaf, stem and pod spot of peas, caused by the fungus Ascochyta pisi. Seed disinfection is unsatisfactory, because the fungus may penetrate deep into the seed, beyond the reach of superficially active disinfectants. Therefore a search was made for disinfectants, penetrating the seeds, using ascochyta-infected seeds for tests. The most effective compounds were the newly discovered antibiotics rimocidin and pimaricin, products of Streptomyces spp. They penetrated the seeds and eliminated internal fungus without impairing germination. An 18-h soaking reduced the percentage of seeds with viable mycelium from 80 to less than 1 %. Dry or almost dry treatment was less effective. A further drawback of these antibiotics was the reversible loss of fungicidal activity inside plant tissue through adsorption, and inactivation by UV radiation.Rimocidin and pimaricin were nevertheless of interest because of their selectivity, being highly toxic to most fungi, but hardly toxic to bacteria and higher plants. Remarkable also was ready uptake by plants and seeds despite their large complex molecules.A new aspect of the parasitism of this fungus was that the fungus was often present in plant parts or whole plants without symptoms. Rarely the fungus was even isolated from seeds, harvested from plants without symptoms. It was also observed that during ripening of the pods many pycnidia appeared outside the limited brown-edged spots, typical for this disease. |
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