Heat treatment to control Colletotrichum acutatum on corms of Anemone coronaria

Anemone corms may be infected with the fungusColletotrichum acutatum, which under certain conditions causes leaf curl and leaf necrosis.A hot-water treatment (hwt) of infected corms for 1.5 h 47.5 °C or 1 h at 50 °C suppressed the disease almost completely. The period of application of hwt between harvest and planting time of corms did not influence the efficacy of hwt. Germination potential of different lots of untreated anemone corms varied between approximately 65% and 95%. Hot-water treatment for 1.5 h at 47.5 °C or 1 h at 50 °C reduced germination only slightly if corms of lots that germinated well without hwt were used. However, germination after hwt was severely reduced if lots with a poor germinating potential were used. Germination potential of hwt-treated corms was restored when they were stored for 4 days in moist vermiculite at 20 °C between hwt and planting. Drying of hwt-treated corms after storage in moist vermiculite reduced germination.A dry heat treatment of infected corms reduced disease incidence too, but results were inconsistent and germination of corms was considerably reduced when control of the fungus was optimal.