Netherlands Journal of Plant Pathology

, Volume 75, Issue 1–2, pp 157–163

The selective effect of heat treatment on the microflora of a greenhouse soil

  • G. J. Bollen
Article

Abstract

Detailed information about the heat tolerance of soil micro-organisms, both pathogens and their nonpathogenic antagonists, is needed for the practice of soil pasteurization.

A device for testing the thermal death point of micro-organisms in soil is described.

The selective effect of heat treatment on the total numbers of bacteria, actinomycetes and fungi of a greenhouse soil (loam) was estimated. Of these groups the fungi proved to be the most sensitive to heat treatment. The heat tolerance of the species of this group was examined in more detail. In comparing the thermal death points of fourteen pathogenic fungi with those of the saprophytic fungal flora many species of the latter proved to be more heat-tolerant.

Samenvatting

In verband met de toenemende belangstelling voor pasteurisatie van kasgrond is een grondige kennis omtrent de afstervingstemperaturen van de bodemorganismen-zowel pathogenen als hun niet-pathogene antagonisten-noodzakelijk. In een voor dit doel geconstrueerd apparaat werd vochtige lucht van verschillende temperaturen door kleine hoeveelheden kasgrond geblazen. Daarna werd de grond geanalyseerd op de overlevende microflora. De schimmels bleken als groep verhitting minder goed te kunnen doorstaan dan de bacteriën en de actinomyceten. Vooral de Oömyceten waren zeer gevoelig. Zeer tolerant waren enkele donkersporige Deuteromyceten en diePenicillium-enAspergillus-soorten, welke een perfecte vorm hebben. De als antagonisten van pathogenen beroemdeTrichoderma-soorten bleken weinig tolerant.

De afstervingstemperaturen van veertien pathogene schimmels bleken lager te liggen dan die van veel saprofyten.

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Copyright information

© Koninklijke Nederlandse Planteziektenkundige Vereniging 1969

Authors and Affiliations

  • G. J. Bollen
    • 1
  1. 1.Laboratory of PhytopathologyWageningen

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