Sensitivity Baselines Of Bipolaris Maydis To Several Fungicides And Resistance Risk Of Its To Prothioconazole In Anhui

Maize is one of the world’s three major food crops in food security,which occupy a very important position,and the plant amount is ranked only second to wheat,rice.It is not only an important food crop,but also an important industrial material and animal feed.In recent years,due to the climate change,the adjustment of crop planting structure,the replacements of varieties and a large number of frequently changing variety in different areas.Maize often suffer from the harm of all kinds of diseases in the process of growth,which seriously affects the yield and quality of Maize,And Maize is one of the world’s three major food crops in food security,which occupy a very important position,and the plant amount is ranked only second to wheat,rice.It is not only an important food crop,but also an important industrial material and animal feed.In recent years,due to the climate change,the adjustment of crop planting structure,the replacements of varieties and a large number of frequently changing variety in different areas,which seriously affects the yield and the quality of Maize,and Corn southern leaf blight is one of them.We used the acquired Bipolaria maydis in anhui province as the test strains,by means of indoor experiments,screened three better reagents that had a good inhibition effect on the growth of Bipolaria maydis in 11 kinds of prospective fungicides.We Analyzed and compared the different sensitivity of Bipolaria maydis to the selected fungicides in different ecological regions in Anhui province and the differences of sensitivity among the three types of medicament,and added field efficacy trials to analyze the control effects of the three kinds of medicament on Bipolaria maydis in Anhui province and to have a more comprehensive understanding of control function that the three kinds of medicament played on the southern leaf blight.And through the way of ultraviolet induction and medicament choosing,we proceeded corn small plaque bacteria of sulfur bacteria resistance risk assessment in Anhui province.The following is the main result of the study:1.We Separated,purified and identified the seven corn leaf samples with small spot typical disease,which were collected from seven corn belts in Anhui province like Hefei,Ming guang,Jin Zhai,Suzhou,Guo Yang,Dang Shan and Sui Xi.Through tissue separation and single spore,the intense 201 strains were isolated and identified all strain morphological characteristics as corn southern leaf blight.2.We adopted the mycelium growth rate method,determined 11 kinds of fungicides with better application value for corn small spot pathogen virulence data inAnhui province.Then We selected several kinds of fungicide single dose which had a stronger virulence effect on corn small spot pathogen.The indoor toxicity measurement results showed that among the selected reagents,Flusilazole had the best inhibition effect on the growth corn small spot pathogens whose EC50 value was0.0227g/m L.Prothioconazole and azoxystrobin also had a good antibacterial effect.We chose flusilazole,prothioconazole and azoxystrobin to proceed subsequent corn southern leaf blight sensitivity to drugs in Anhui province to establish baseline test.3.According to the geographical location and climate differences,we divided the separated corn small plaque bacteria into three ecological zones,to compare sensitive baseline differences to the corn southern leaf blight in different ecological zones.Among them,Hefei and Mingguang is the main producing areas of maize in the south of Huaihe River,Suzhou,Guoyang and Suixi,and Dangshan is the main producing areas of maize in the north of Huaihe River.Jinzhai is the sporadic planting area of maize in Dabie Mountain.After the sensitivity test,nine sensitive bases of the corn southern leaf blight to three medicament in different ecological zones and three sensitive bases to three tested medicament of the corn southern leaf blight in An hui province.The results showed that the sensitivity of to the three fungicides was successively the Dabie Mountains,the south of the Huaihe River and the north of the Huaihe River from the stronger to the weaker.Among them,the sensetivity of corn southern leaf blight to Flusilazole was the strongest and the sensitive baseline was the smallest.The sensitivity of prothioconazole was the second,and the sensitivity of Azoxystrobin was the worst,but all the three fungicides had a good inhibitory effect on the mycelial growth of maize leaf spot,and from the sensitive baseline,we could see that the sensitive baselines of the three fungicides were all at a low level.4.The Bipolaris maydis were cultured by corn culture CM medium,Until it produces a lot of spores later,Wash the conidia with sterile water and microscopically,The spore concentration was about 1 × 105 spores per milliliter of the spore suspension.A certain amount of fungicide was applied to the maize plants two days before and after the spore suspension,And the same amount of water as a control,7days after vaccination in the field of corn spot disease occurred.Through the field efficacy test,it was found that flusilazole was the best in the prevention and cure of maize leaf spot,and the therapeutic effect was significantly stronger than the preventive effect,the prevention effect was 74.17%,the therapeutic effect was81.16%;prothioconazole was used to control corn spot The effect of the disease was61.30%,the therapeutic effect was 68.89%,the therapeutic effect was stronger than the preventive effect;the control effect of the azoxystrobin was the worst among the three,the preventive effect was 52.74%,the therapeutic effect was 51.13%,Protection and treatment of the role of almost.5.In this studythe Sensitive strain HF1 in the strain of corn leaf spot separated from Hefei area as testl strain and prothioconazole as supplied test fungicides.Though two ways of ultraviolet induction and fungicide selection,we respectively got 1 and 4resistant mutants.The Mutation frequency of ultraviolet induction method was1.25×10-8,and choice of the mutation frequency of 0.011.Among them,there were two resistance plants and three low resistance plants and no high resistance plants.Five resistant mutants were tested from four aspects: resistance level,genetic stability,mycelial growth rate and pathogenicity.The results were compared with the corresponding sensitive strains,and their biological characteristics were analyzed.The results showed that the toxicity resistant mutants declined in varying degrees in genetic stability,mycelial growth rates,resistance level and causative force four aspects.Though toxicity resistant mutant frequency,we judged corn southern leaf blight was a low risk of resistance to Prothioconazole.It provides reference for field science fungicides and the development of anti-toxicity treatment methods.