Occurrence Regularity And Control Of Job's-tears Smut From Coix Lacryma-jobi L. In Anlong County

Job's tears smut is a characteristic medicinal and food crop in anlong county,which has great medicinal and edible potential.Ustilago coicis Bref.was a common occurrence in Job's tears smut.It seriously affected the quality and yield and could reduce the yield of coix lachrymajobi L.by 30%-50%,Even in severe cases,the production can be reduced by 80%.The main methods to prevent and control Job's tears smut were mixing fungicide and soaking in warm soup.For controlling job?s-tears smut,improving the quality and yield of Coix lacryma-jobi L.In this study,through separation and identification of pathogenic bacteria and selected for inhibitory effects of fungicide by mycelial growth rates.The aim of the field experiment was to investigate fungicide and control effect of Job's tears smut.The main findings are as follows:1.In 2017,we gathered and diseases investigation of Job's tears smut from the Anlong county,Guizhou Province.While the condition is most often asymptomatic of seedling stage.The main source of primary infection comes from hypha,akinetes and sclerotiums over-wintering in the bulb,residues of diseased plants and the soil.tillering and flowering stage was finding disease plant.It is presumed that chlamydospore may be the major primary infection source of Job's tears smut and begin to infect the panicles of Coix seeds.2.In this study,tissue separation were conducted to pathogen,and identified the pathogen of job's-tears was Ustilago coicis Brefeld combined with morphological characteristics with molecular biology methods.3.It is the best to soak seeds in water at 70 ? for 20 minutes,Average grain output per mu has reached 241.08 kg.The incidence of job?s-tears smut only5.56%.4.Through the test,we selected five high toxicity fungicides against.They were37% difenoconazole WG and 40% myclobutanil SC and 40% prochloraz EW.their EC50 values were 0.2157 ?g / mL?2.8583 ?g / mL?4.3901 ?g / mL respectively.5.We selected fungicides to control the job?s-tears smut in field.They were 37%difenoconazole WG and 40% myclobutanil SC and 40% tebuconazoleo·prochloraz,their control effect reached 100%.