The Biological Characteristic Of Ustilaginoidea Virens (Cooke) Tak And Disease Epidemic Of Rice False Smut

Flase smut of rice(FSR) caused by Ustilaginoidea virens(Cook)Tak,is widely dispersed over the world and a widespread disease in the major of rice planting area of China.With changing from rice varieties and rice cross,it has aggravated the yield loss of rice gradually. The objective of present paper was to study the biological characteristics of Ustilaginoidea virens(Cook)Tak,the occurrence of FSR and its control techniques.The optimal medium of Ustilaginoidea virens(Cook)Tak was determined by Optimizing the medium from carbon source,nitrogen source,inorganic salt and PH.For mycelium growth,the best carbon-source was sucrose,the best nitrogen-source was CaNO₃,the suitable temperature was 28℃,and the suitable PH was 6-7,.There was only a few of conidia formed by hypha balls of the fungus in PS liquid medium.The colonies of WW,CH and SC on medium could usually produce abundant chlamydospores,around the colonies or dispersing on the whole colonies.The airborne spores of Ustilaginoidea virens(Cook)Tak were trapped daily through the whole growing season.The quantity of airborne spores were always increasing from August 5th to August 31th..After that time the spores quantity was at steady period.The spores quantity on day were more than that of night in clear daytime,but the spores quantity on day were similar to that of night in overcast daytime.The control by fungicide in the field demonstrated that 6%Jingangmycin·bacillus subtilis WP can be used for controlling of Ustilaginoidea virens.The best average control effect of the fungicide to rice false smut was 74.4%.Furthermore,6%Jingangmycin·bacillus subtilis WP(120g/667m²) was applied to control rice false smut at different stages of rice growth in FengTai country and TongCheng city.The results showed that the control effect of the fungicides decreased with the postponement of the application time.The aptimal application time at the flag auricle stage of rice the efficiency reach top level.In addition,seventeen reserve rice varieties derived from Anhui Provinceresistance to rice false smut in the field was identified.The result revealed that Yanjing NO 9,80you226,Tianxie No 1,AO1xian and lvjingnuoNo6 displayed moderate resistance,AO3xian,Yangjing636 and AO8jing displayed susceptibility,other nine varieties displayed moderate susceptibility.yield occurrence of rice false smut in that period was investigated.the series of liangyou displaying susceptibility,and Xinliangyouxiang4 displaying resistance were found.