Effects of temperature and fungicides on Chrysosporium pannorum (Link) Hughes

C. pannorum was isolated in low frequencies and only in the colder months from untreated soil and leaves and from those treated with Captan, Dicloran and Thiram. The fungus was isolated throughout the year as the major species from Verdasan-treated substrates and it occurred with increased frequencies immediately after application of the fungicide. The abundance of C. pannorum on Verdasan-treated substrates was attributed to the ability of the fungus to utilise the fungicide rather than to the absence of faster growing competitor species. C. pannorum was shown to be a slow growing and moderately cellulolytic fungus with maximum rates of growth, germination and cellulose clearing at between 15 degrees and 20 degrees C. Increasing concentrations of the fungicides retarded or prevented growth and activity of the fungus. C. pannorum could grow, germinate and clear cellulose in higher concentrations of Verdasan than could other species studied. C. pannorum was more tolerant of HgCl2 than of Verdasan. The fungus could detoxify up to 3 micrograms/ml active ingredient of Verdasan (= 120 micrograms/ml of the formulated fungicide) in liquid culture.