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  • Ida Blok
  • Netherlands Journal of Plant Pathology
  • 2005
Oösporen vanBremia lactucae kunnen worden verkregen door bladschijfjes van sla te inoculeren met een gemengde conidiënsuspensie van twee fysio's van de schimmel, die de twee compatibiliteitstypen (B1 en B2) vertegenwoordigen. Wanneer het bladweefsel geheel vergaan is, worden de schijfjes met oösporen samen met het onderliggende filtreerpapier op een dunne(More)
  • Ida Blok
  • Netherlands Journal of Plant Pathology
  • 2005
Culture filtrates ofPythium spp. (mainlyP. sylvaticum) were studied as such and after purification and separation by paper chromatography. A bio-assay was developed in which the elongation of seedling roots was used as a criterium. The following results were obtained from these bio-assays: 1. P. sylvaticum is able to produce auxin under laboratory(More)
From mature lettuce heads with bottom rot symptoms severalPythium species were isolated, two of which were studied further. Pathogenicity tests with both fungi have been carried out only with seedlings. P. uncinulatum sp. nov. was isolated frequently. Its relation to otherPythium spp. with spiny oogonia is discussed. It proved to be very pathogenic to(More)
Results are given on the occurrence of sexual compatibility types of seven isolates ofBremia lactucae originating fromLactuca serriola (prickly lettuce). It is concluded that the isolates studied are heterothallic. Both compatibility types (B1 en B2) were determined, but type B2 was prevalent. Sexual recombination ofB. lactucae isolates originating from(More)
A 1∶1 mixture of spores of the physiologic races NL5 and NL6 ofBremia lactucae was sprayed on leaf discs of the lettuce cultivar Olof. The resulting oospores were allowed to germinate on seedlings after a two-month ripening period. Monospore lines of 49 of the 79 recovered isolates were tested on cotyledons and leaf discs of a differential series for(More)
Local necrosis, p r o d u c e d soon after p lan t infection by a pa thogen , is usually called a hypersensi t ive reac t ion and is cons idered an impor t an t feature o f incompat ib i l i ty . Dur ing their s tudy on downy mi ldew in lettuce (Lac tuca sativa L.), Mac lean et al. (1974) detected necro t ic host cells af ter pene t ra t ion by Bremia(More)
  • Ida Blok
  • Netherlands Journal of Plant Pathology
  • 2009
In recent studies concerning the occurrence of Pythium species in agricultural soil, many isolates from almost every soil sample appeared to belong to Pythium sylvaticum Campbell & Hendrix. Van der Plaats-Niterink (1968) already reported this fungus in various soils from different parts of the Netherlands. Domsch et al. (1968) found P.sylvatieum in soil in(More)
Als uitgangspunt bctreffende bet gebruik van bestrijdingsmiddelen in de landbouw zal in vetband met de volksgczondheid de vraag worden gesteld of bij de beoordeling volstaan kan worden met de uitkomsten van residubepalingen in landcn tuinbouwgewassen in combinatie met de toxicologische gegevens. Ter beantwoording van deze vraag zal allereerst aandacht(More)
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