1. In order to control a disease on Japanese parseley (Oenanthe javanica) soil treatment and spraying of some fungicides was carried out on paddy field at Kuroda, Matsue city,
2. Both procedures, especially soil treatment was effective for the prevention of this disease, judging from the analysis of variance and X^2 test. The most excellent result was obtained by the soil treatment of 1 : 5,000 solution of Captan, 1 : 10,000 and 1 : 20,000 solution of PCP followed this.
3. No harmful effect of the chemicals on the suseepts was recognized comparing the control lot,
4. Ratio of fatty compounds to protein nitrogen in a mycelium of Pythium is greater than that of Sclerotinia and Botrytis. Different fungicidal effect of mercyury compounds to Pythium, Sclerotinia and Botrytis is discussed along this line.