Being the method of controlling the useful plant or plant pathogenic bacteria characteristic disease for those plant propagation materials, the chemical compound of the following formula I of the quantity which is effective to sterilization (in formula, R1 is trifluoromethyl or jihuruoromechiru, and R2 is hydrogen or methyl.)Or the method of including the fact that tautomerization isomer of the above-mentioned chemical compound, is applied to the above-mentioned plant propagation material, especially, is an effect in control or prevention of the true germ illness of the crop.有用な植物又はそれら植物繁殖材料に対する植物病原菌性の疾患を抑制する方法であって、殺菌に有効な量の、次の式Iの化合物(式中、R1はトリフルオロメチル又はジフルオロメチルであり、そしてR2は水素又はメチルである。)、又は上記化合物の互変異性体を、上記植物繁殖材料に適用することを含む方法は、特に、作物の真菌病の抑制又は防止に効果がある。
