A sieving and floatation technique, using 2% aqueous solution of hydrogen peroxide was developed for extraction of sclerotia of Rhizoctonia solani from soil. Sclerotia were extracted without loss of infectivity. Plant debris particles colonized by the fungus also floated on the solution. Few Rhizoctonia remained in sieved and sedimented soils.
The most part of conidia and germtubes of Fusarium oxysporum f. sp. raphani placed in natural and crab-shell amended soils are flattened within several days. The observations suggest that the occurrence of flat conidia and germtubes is not affected by any direct action of other soil microorganisms, thus being regarded as a process of autolysis.
“Susogare” of garden pea in Tokushima prefecture is characterized by yellowing, withering of under leaves and root rot. Aphanomyces euteiches was isolated from diseased pea roots. Peas, inoculated with this fungus, showed same symptoms as observed in field. A. euteiches was detected in 93 of 122 fields tested. It is considered that A. euteiches causes the “Susogare”.