MYCOFLORA OF GROUNDNUT RHIZOSPHERE SOIL AND GEOCARPOSPHERE ON LIGHT MEDIUM AND HEAVY SOILS AND ITS RELATIONS TO ASPERGILLUS FLAVUS

A comparative study was carried out in groundnut fields in Israel of the mycoflora of rhizosphere (R) and soil adhering to geocarps (G) and of the soil (S). Of a total of 157 fungal species isolated and listed, 133 occurred in R, 96 in S, and 86 in G. Ten species considered rare or worthy of special note are briefly discussed. Species of Aspergillus were most numerous in heavy soil, species of Penicillium in light soil, and species of Fusarium in medium soil. Penicillium funiculosum and P. rubrum were the species occurring with greatest frequency, and these were equally common in R, S, and G of light and medium soil. Soil inoculation with A. flavus depressed the number of species in the mycoflora of R and S. Quantitative comparison of R, S, and G on the three soils showed that numbers for R exceeded those for S and G, for P. funiculosum and P. rubrum on all soils, and for several Aspergilli on heavy soil. Among fungi more prevalent in S than in R and G was A. flavus on medium and heavy soil. No special affinity of any one of the 3 major groups (Aspergillus, Penicillium, Fusarium) for the mycoflorae of R or S or G has been found. The relative number of colonies of all fungi in R and S (R/S ratio) was in almost all cases in excess of 1 on all soil types. © 1969 Dr. W. Junk N.V.