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Ecology and Epidemiology

Mycophagous Amoeboid Organisms From Soil that Perforate Spores of Thielaviopsis basicola and Cochliobolus sativus. T. R. Anderson, Graduate Student, Department of Botany, University of Toronto, Toronto, Ontario, Canada M5S 1A1.; Z. A. Patrick, Professor, Department of Botany, University of Toronto, Toronto, Ontario, Canada M5S 1A1. Phytopathology 68:1618-1626. Accepted for publication 16 June 1978. Copyright © 1978 The American Phytopathological Society, 3340 Pilot Knob Road, St. Paul, MN 55121. All rights reserved.. DOI: 10.1094/Phyto-68-1618.

Direct visual evidence in laboratory culture chambers showed that certain free-living, soil-inhabiting, amoeboid organisms perforated and fed on chlamydospores and mycelium of Thielaviopsis basicola and conidia of Cochliobolus sativus. The annulations and performations of fungal spores observed in the culture chambers were similar to those found in spores incubated in field soils obtained from various locations in Canada. The systematic position of the mycophagous amoebae seems to be with the protozoan order Proteomyxida and the family Vampyrellidae, but species identification cannot be made with certainty because the taxonomy is still controversial. Based on their widespread distribution in arable soils and their marked predacious activity it is postulated that the mycophagous soil amoebae may play a significant role in the ecology of soilborne fungal plant pathogens and their biological control.