Biological control of Botrytis spp. by Ulocladium atrum : an ecological analysis

Research output: Thesisinternal PhD, WU


Plant pathogenic fungi from the genus Botrytis cause economically important diseases in a wide range of crops during the production phase as well as post harvest phase. Control is based on the frequent use of fungicides. Alternative approaches for control are studied because of the development of fungicide resistance in the pathogen and environmental concerns.

The fungal saprophytic antagonist Ulocladium atrum is an effective biological control agent of B. cinerea in cyclamen. U. atrum may also be effective against B. cinerea in other crops and against other Botrytis spp. The biocontrol effect of U. atrum is based on a competitive interaction with B. cinerea in plant tissue. An immuno-histological technique was developed to visualize the interaction between the mycelia of Botrytis spp. and U. atrum in plant tissue and quantify colonization levels. Nutrient competition was found to be the dominant antagonistic mechanism between the species and pre-emptive colonization of plant tissue by U. atrum was identified as the most promising biocontrol strategy. Necrotic plant tissue is the primary target for U. atrum applications, since this is the (only) niche available to both Botrytis spp. and U. atrum .

Pre-emptive colonization of naturally necrotic tissue by U. atrum was highly effective against B. cinerea in cyclamen, whereas U. atrum applications against B. elliptica in lily were ineffective. A comparison of both pathosystems suggests three criteria that govern the potential success of U. atrum as a biocontrol agent. 1) There must be a niche in which U. atrum competes with the pathogen; 2) The competitive ability of U. atrum in this niche has to be sufficient to allow for competitive exclusion of the pathogen. 3) The niche from which the pathogen can be excluded has to be essential for disease development. Colonies of U. atrum have lower radial growth rates than those of the Botrytis spp. studied. In practical biocontrol, this competitive disadvantage of the antagonist can be overcome by applying a high density of its conidia in a uniform distribution on the target tissue.

Original languageEnglish
QualificationDoctor of Philosophy
Awarding Institution
  • Rabbinge, R., Promotor, External person
  • Koehl, J., Promotor, External person
  • van der Werf, Wopke, Promotor
Award date1 Dec 1999
Place of PublicationS.l.
Print ISBNs9789058081490
Publication statusPublished - 1999


  • botrytis cinerea
  • plant pathogenic fungi
  • biological control
  • deuteromycotina
  • mycelium
  • dematiaceae


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