Inhibition of the Crown-rot Disease Fungus, Sclerotium delphinii Welch

Abstract

IN 1952, I reported¹ the inhibition in vitro of the crown-rot fungus, Sclerotium delphinii Welch, by two species of Penicillium, P. brevi-compactum and P. charlesii. In vivo experiments were set up to demonstrate the practical utilization of these penicillia as agents in combating the crown-rot fungus disease. For this purpose the penicillia were grown in large quantities in Czapek–Dox medium for seventeen to eighteen days on a rotary shaker at room temperature. The culture fluid was then filtered and the filtrate was poured into standard greenhouse flats, containing soil which had been artificially infested three days before with sclerotia of S. delphinii. Controls were also set up, using Czapek–Dox medium, in flats of similarly infested soil. A few days after filtrates of different concentrations were added to the flats, nine plants of Mazus reptans and Ajuga reptans (two rock-garden plants extremely susceptible to S. delphinii) were planted in each of the different flats.