一、前言关于侵入水稻叶鞘形成病斑而造成损伤的菌核病菌,中田,河村两氏已经进行过较详细的研究,并于40年前就作过报导。以后,在这些菌核病之中,对水稻产量影响较大的小粒菌核病(小球、小黑),纹枯病受到重视,引起全国开展研究,现在对其生态,防除措施等等已经明确。可是关于这两病以外的很多菌核病的调查研究,因认为对水稻直接被害较少而 I. Introduction Sclerotinia sclerotiorum, Nakata, and Kawamura have been studied in more detail with respect to the lesions that invade the rice sheath formation, and were reported 40 years ago. Later, in these sclerotinia, the small sclerotinia (pellets, black) that have a greater impact on rice yield, and the sheath blight were taken seriously, causing the nation to conduct research. Now that its ecology, control measures and so on have been clear. However, many studies on the sclerotinosis other than these two diseases were considered because less direct damage to rice