Field survival of sclerotia of Typhula incarnata and of T. ishikariensis biotype A

Survivorship patterns of sclerotia of Typhula incarnata Lasch:Fr. and of T. ishikariensis S. Imai biotype A were compared under field conditions from May to November, using plastic containers with 10- or 250-μm mesh. Minute arthropods always existed in the 250 μm mesh containers, but the difference in mesh size did not affect the viability of sclerotia. Percent viable sclerotia of T. incarnata decreased from 86.0 to 24.2 for those placed on the soil surface, to 5.0% for those buried in soil 81 days after treatment, and then remained the same until the end of the experiment. Most of the T. ishikariensis biotype A sclerotia survived; however, in some containers buried in the soil, half to all of the sclerotia were dead. Several mycoparasites were isolated from both types of sclerotia. The possibility of biological control by reducing the number of sclerotia is discussed in relation to the difference in epidemiology of Typhula incarnata and T. ishikariensis biotype A.