VIEW ARTICLE

Soil Fungistasis: Evidence for an Inhibitory Factor. Maureen Romine, Research Assistant, Department of Botany and Plant Pathology, Colorado State University, Fort Collins 80521; Ralph Baker, Professor, Department of Botany and Plant Pathology, Colorado State University, Fort Collins 80521. Phytopathology 63:756-759. Accepted for publication 27 December 1972. DOI: 10.1094/Phyto-63-756.

Bioassay techniques previously used to detect germination inhibitors from soil were modified to increase their sensitivity. Nutrients, which tend to mask fungistatic inhibitors, were removed from Difco purified water agar discs by washing in running tap water for 90 min. Conidia of Helminthosporium sativum and Fusarium solani f. sp. phaseoli, not requiring exogenous nutrients for germination, were placed on these washed discs. Reduction of germination due to volatiles was similar to that observed for conidia in direct contact with seven soils of various textures and hydrogen ion concentrations collected from different locations. Inhibition due to volatiles was not detected in nonwashed discs. These results suggest that the phenomenon of soil fungistasis is due to an inhibitory factor which can be annulled with appropriate nutrients.