Sobrevivência e viabilidade de escleródios de sclerotium cepivorum no solo

Abstract

In a field experiment, the survival and viability of sclerotia from Sclerotium cepivorum in the soil was quantified. One hundred sclerotia were multiplied on PDA culture medium and stored in fabric bags. In a wooden frame containing soil, 12 replicates were placed respectively on the surface and buried at 10 cm depth. Every month, bags were removed from each position, washed in water and subject to compression with a histological needle to verify whether they were intact. Intact sclerotia were sterilized with 70% ethanol for one minute, 1.25% sodium hypochlorite for three minutes and sterile water for washing; then, they were deposited on plates containing PDA culture medium and placed in a growth chamber at 20° C without light. During incubation, germinated sclerotia were counted until the seventh day. Sclerotia collected from the surface lost their viability after three months, while buried ones remained viable until the seventh month. S. cepivorum sclerotia on the soil surface tend to lose their viability in a shorter period than buried sclerotia.