| Rhizoctonia Kuhn is kind of fungus with wide distribution and can infest many plants. It is a very large group, often result in series plant diseases by anastomosis group (AG) and cause large economic loss. Currently, there is little information available on the characteristics of the fungicides and control effect to the AG in the literature. In China, the susceptibility of different strains belong to the AG1-IA intraspecific group (ISG) to different fungicides were studied, while there is no information on the susceptibility of other AG to different fungicides. Chongqing is a serious AG infested area. In order to manage this kind of disease effectively, this paper studied the susceptibility of 12 anastomosis group (AG-2-1 s AG-3, AG-4, AG-A, AG-C1, AG-D, AG-E, AG-F, AG-K, R. solani, 290, BM9) to 7 fungicides (carbendazim, thiophanate-methyl, thiram, fenaminosulf, kocide 2000, Jingangmycin, and chlorothalonil) which commonly used to control the soreshin, and sheath blight in the laboratory by culture in vitro method of "paper dish method" and "fluid culture method". The culture characteristics of AG and the susceptibility of different strains to the same fungicide were investigated. All of these information could provide very important theory basis to the screening and changing of fungicide\ rotation and popularization of resistant crops and making of manage strategy.According to the information in the literature, the culture temperature was determined, and then according to the result, the culture time of "paper dish method' was 48h, and 'fluid culture method' was 72h.The statistical analyses of the data were performed on the computer using statistical software such as Excel and SPSS 10.0 for Windows. The percentage data was transformed to arcsin-square-root value before multiple range test was performed.The major results are as follows:1. The classification of anastomosis group (AG)The result showed that there is significant difference in the following aspects among different anastomosis groups. These including the growing velocity of hyphae, the color\ shape\ structure and size of the mycelitha, the color of the colony, number and distribution of the surfance villus, the number of the hypha, and the color of the culture medium, and so on. Based on the culture characteristics, it was found that the characteristics of colony, hyphae and the color of culture medium are completely same between AG-A and AG-C1, however, the others are different from each other. So the AG-A and AG-C1 were specially studied and the following conclusion was achieved: the two groups (AG-A and AG-C1) are intraspecific group (ISG).2. The inhibition of different fungicides to the AGsBoth Jingangmycin and fenaminosulf have good inhibition effects on 12 AGs, and the effect of fenaminosulf is the best. All 7 tested fungicides have effective inhibition to R. solani.Carbendazim has the effective inhibiting effects on AG-E> AG-CK AG-A. it might be used to control those diseases infested by the three AGs for paddy, maize, Chinese sorghum, millet, soybean, leaf mustard, beet, spinach, tea, dragon spruce, larch, ginseng, hemp, and so on.Thiophanate-methyl can effectively inhibit the growth of AG-4 and AG-A. It might be used as the important theory basis of choosing the fungicides to control those diseases infested by these two groups for maize, paddy, hot pepper, potato, eggplant, pea, rape, cabbage, carrot, beet, buckwheat, cypress, millet, and so on. It could also be used to control sharp eye spot of wheat which is mainly caused by AG-D.Thiram can effectively inhibit the growth of AG-K, this result might be as a theoretical basis to select fungicide to control the crop diseases caused by AG-K on millet, peanut, strawberry, chrysamthemum, beet, carrot, fennel, and so on.Chlorothalonil can effectively inhibit the growth of AG-2-1 and 290. It might be used to control the crop diseases caused by these two groups on wheat, wild cabbage, rape, cabbage, jujube, and so on.The inhibition effects of Kocide to 12 AGs...
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