EFFECT OF PLATING MEDIUM AND INCUBATION TEMPERATURE ON GROWTH OF FUNGI IN SOIL-DILUTION PLATES

Abstract

The effects of 20, 25, or 30 °C incubation temperatures for dilution-plates and of five plating media (Ohio Agricultural Experiment Station Medium (OAES), Liftman"s crystal-violet agar, dextrose-peptone agar, soil-extract agar, and glucose-nitrate soil-extract agar) on total numbers and types of fungi isolated from two soils (sugar beet or corn cropped) by a soil-dilution plate method were determined. The data revealed that significant differences existed among the three variables as well as their interactions. Although numbers of colonies of fungi isolated were not affected significantly, the types of fungi (number of individual genera) isolated were significantly greater in sugar beet than in corn cropped soils. In nearly all instances, the greatest total number and types of fungi were isolated at temperatures of 20 or 25 °C. Although each medium appeared to favor one or more groups of fungi, the overall frequency and distribution of fungi was essentially the same on all media. On the basis of its transparency, total number and types of fungi isolated, the elimination of bacteria and actinomycetes, and its restriction of rapidly growing fungi, the OAES medium was deemed the most suitable for use in the soil-dilution plate method.