Study On Species And Distribution Of Cotton Root Rot Disease And Its Control Techniques In Southern Of Xinjiang

Cotton is one of the main cash crops in Xinjiang.But it is also the most serious areas of cotton seedling disease in China.The widespread occurrence of a variety of seedling root rot diseases has been seriously affected the yield and quality of cotton in Xinjiang.In this study,a large area survey was conducted on the occurrence of root rot diseases in southern Xinjiang,which is major cotton areas in southern Xinjiang,And through the sample collection,the pathogen was isolated and identified.Molecular testing was carried out for all diseases samples.The pathogenicity of the isolates was determined in each areas.On the basis of these,the method of virulence determination and field seed coating agent efficacy test was used to screen the disease prevention agent.In order to find out the pathogens of the Xinjiang cotton seedling root rot disease,and screen out effective fungicides to control them.By establishing the key control techniques,the theoretical guidance and technological support were provided for the prevention of cotton seedling root rot.Field investigation and sample identification showed that:There are two kinds of cotton root rot diseases in southern Xinjiang cotton area.Respectively,damping-off caused by Rhizoctonia solanidamping-off andred rot caused by Fusarium verticillium;Among them,the occurrence of damping-off is more common,and the frequency of pathogen isolation is higher.The occurrence of red rot has obvious regional,but in several counties occur more,the pathogen isolation frequency is relatively low.Using the Specific primers which were report in article to detect all pathogens that collected from each areas show that:Two kinds of root rot disease pathogens have a higher detection rate;The detection rate?about 80%?of Rhizoctonia solani was significantly higher than that of Fusarium verticillium?about 56%?,and the detection areas of Rhizoctonia solani?all counties and cities,80%of the township?More than the detection areas of Fusarium verticillium?all counties,56%of the township?;indicating that the two bacteria are widely distributed in southern Xinjiang,but the distribution of Rhizoctonia solani is more extensive.The results of the pathogenicity test showed that:The pathogenicity of Rhizoctonia solani was significantly higher than that of Fusarium verticillioides among the two pathogenic strains,there were significant differences in pathogenicity between the strains from different regions,and there were significant differences in pathogenicity between the same strains.The results of virulence determination showed that:six kinds of fungicides?80%tolclofos-methyl?50%prochloraz-manganese chloride complex?75%Iprodione?75%difenoconazole?80%mancozed?70%metiram?had a greater toxicity to Rhizoctonia solani((EC₅₀0 between 11.9 and 265.3)),and six kinds of fungicides?70%metiram?80%mancozed?50%prochloraz-manganese chloride complex?45%Thiram·Thiophanate-Methyl·Sulphur?75%NATIVO?36%Trichloroisocyanuric acid?had a greater toxicity to Fusarium verticillioides(EC₅₀0 between 91.3 and 308.6).Among them,50%prochloraz-manganese chloride complex showed better effficiency in the two kinds of disease treatment.The effects of the two kinds of pathogens on the seed coating after mixed inoculation showed that:tolclofos-methyl+prochloraz-manganese chloride complex?fludioxoni+azoxystrobin+fludioxonil+ metalaxyl-M?prochloraz-manganese chloride complex+Trichloroisocyanuric acid,Three complex formulations have an effective therapeutic effect on two diseases,the integrated control effect above 86%.