LONG-TERM SURVIVAL OF SCLEROTIA OF SCLEROTIUM-CEPIVORUM AND STROMATINIA-GLADIOLI

In an experiment with pure‐culture sclerotia of Sclerotium cepivorum and Stromatinia gladioli a large proportion of the sclerotia survived burial for 20 years in the field in the absence of host plants. Some evidence for metabolic activity or leakage leading to the gradual erosion of the sclerotial contents was obtained with S. cepivorum. The results of other experiments suggested that, for unknown reasons, a variable proportion of sclerotia formed naturally on infected plants may decay shortly after their formation, but those which survive beyond this limited period are likely to remain viable for many years. The viability of sclerotia was also reduced by prolonged flooding, but the period for which land would have to be under water excludes this as a method of eliminating sclerotia from infested land in the UK. Treatment with the mycoparasite Teratosperma oligocladum did not affect the survival or infectivity of sclerotia of S. cepivorum or S. gladioli. Copyright © 1990, Wiley Blackwell. All rights reserved