Effect of soil fungi communities on the growth of damping-off pathogens in relation to incubation temperature and medium pH

Abstract

Four communities of saprotrophic fungi from a forest nursery soil were tested for their effect on the in vitro growth of damping-off pathogens: Rhizoctonia solani, Fusarium avenaceum, F. culmorum, F. oxysporum and F. solani in relation to incubation temperature (5, 10, 15, 20 or 25°C) and medium pH (4.3; 5.6 or 7.5). The soil fungi communities weakly suppressed the growth of pathogens studied only at the lower temperatures (5 or 10°C). At the higher temperatures the communities tested supported the growth of all pathogens. The supporting effct was increasing with the increase of temperature, independently of pH. The effect was highly dependent on incubation temperature and not dependent on medium pH (P<0.05, analysis of variance). Duncan's multiple range tests indicate no significant differences (in the majority of combinations) in the effect of soil fungi communities on the in vitro growth of tested pathogens between temperatures 15, 20 and 25°C, independently of medium pH. The growth of the pathogens studied was suppressed mainly by: Gliocladium catenulatum, Trichoderma atroviride, T. koningii, T. viride, Truncalella truncata and Zygorrhynchus moelleri