This study was made in order to determine which Gibberella species were occurring on rice stems and seeds in the field, and their survival 5 months after harvest time.
An average 12% of plants infected with ´Bakanae´ disease occurred in 4 fields planted with non-treated seed.
Prior to harvest, more perithecia of Gibberella moniliformis occurred on infected rice stems than of Gibberella rosea. But Gibberella rosea was most common on the seed, and perithecia of this species also survived best until spring.
F. moniliforme, F. roseum and Ophiobolus sp. were isolated from seedlings planted from naturally infected seed at the rates of 10, 25 and 8% respectively and from infected stems at rates of 3, l0 and 2% respectively. Perithecia of Gibberella rosea survived through the winter on naturally infected rice stems when kept dry indoors, buried in field soil, or places in straw stockes in the field. They did not survive on straw left on the soil surface during the very cold and dry conditions of the 1976-´77 winter.
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