|Title:||疑似紋枯病之水稻菌核性病害||Other Titles:||Several Sclerotial Diseases Regarded as Pseudo Sheath Blight Disease of Rice||Authors:||游復明
|Issue Date:||Jan-1991||Publisher:||農業試驗所||Start page/Pages:||83-102||Source:||農業試驗所特刊第32號||Conference:||稻作病害研討會專刊||Abstract:||
A new type of sheath blight disease of rice was first discovered in Yaaguchi Prefecture of Japan in 1959.The symptom of the disease was very similar to that of sheath blight. The main differences of the symptoms between the new disease and sheath blight were that the lesions of the new disease were much darker than that of sheath blight, and there was no sclerotium formed on the surface of the lesion of the new disease. The casual pathogen of the new disease was identified as Corticium sp. by Nonaka in 1964, and it was proved to be more tolerant against arsenic compound than that of sheath blight pathogen. The disease was then called pseudo sheath blight disease in 1966 by Watanabe in order to distinquish from sheath blight disease. However, in 1970 another new disease was also discovered in Ishigawa Prefecture by Taketani and Tamura. The symptom of the disease was also very similar to that of sheath blight disease, and the disease was also more tolerant against arsenic compound than that of sheath blight disease. Therefore, the disease was temporalily called sheath blight like symptom, and the causal pathogen was identified as Pellicularis sp.
In order to solve the confusing problem of taxonomy, in 1977, Watanabe , Nonaka and Oniki collected the causal pathogens found in Yamaguchi and Ishigawa Prefecture and Rhizoctonia solani III B isolated from rush stem rot for further studies. Finally they concluded that these three fungi were actually the same organism, and identified as R. solani III B and anastomosis belonged to AG2-2. The disease was then called brown sheath blight disease.
However, aside from brown sheath blight, there are several other scierotial diseases that will form sheath blight like lesions. These scierotial diseases are bordered sheath spot, brown sclerotium and grey sclerotium etc. Therefore, it is now generally agreed that pseudo sheath blight is a general term of several sclerotial diseases (except for sheath blight) that will form sheath blight like lesions.
General speaking, the pathogenicity of these scierotial fungi were weaker than that of sheath blight pathogen, and these sclerotial diseases occurred much later than that of sheath blight. Therefore, pseudo sheath blight disease would not result in reduction of rice grains directly. In stead, it could decrease the quality of rice grains. Since pseudo sheath blight always occur together with sheath blight in the rice field, that the real effects of pseudo sheath blight on the rice production are still unknown.
In Taiwan, pseudo sheath blight disease occurred commonly in the southern area. According to author¡¦s field observation, the lesions of brown sheath blight and borded sheath spot could reach to the leaf sheaths of the flag leaves. Since most pseudo sheath blight fungi will grow much better under high temperature, therefore the importance of pseudo sheath blight disease in Taiwan needs to be further studied.
|Appears in Collections:||植物病理組|
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