高うね処理によるコムギ雪腐大粒菌核病の発生促進法の再評価

抄録

At Kitami Agricultural Experiment Station, the high-ridge cultivation（HRC）method is used under field conditions to test the resistance of winter wheat and the effect of fungicides to Sclerotinia snow mold caused by Sclerotinia borealis. It has been considered that the HRC method eliminates other snow molds concurring with S. borealis. However, recently other snow molds may be eliminated using specific fungicides. S. borealis has occurred less often in recent years owing to climatic changes in winter but still remains an important disease in Kitami. In this report, I critically reassessed the effectiveness of the HRC method in terms of temperature and disease severity. The HRC method reduced soil temperature,increased frost damage in plants, and promoted the incidence of S. borealis. Under a persistent snow cover,the ground temperature in HRC was approximately −1℃, which favored disease occurrence. The disease occurred severely in HRC, whereas there was little occurrence in the control level-row cultivation. In conclusion, the HRC method is effective in increasing the severity of the Sclerotinia snow mold and it enables consistent occurrence of the disease despite recent warm winters.