Research On The Incidence Conditions And Chemical Control Technology Of Rice Bakanae Disease In Heilongjiang Province

Rice is the main grain crop in China,and Heilongjiang province is the main rice production base of China.In recent years,rice bakanae disease occurred severely in the process of seedling in Heilongjiang province,posing a serious threat to rice production of rice planting area in Heilongjiang province.In this study,the main varieties planted in Heilongjiang province were selected.Based on the identification of the types and pathogenicity of rice bakanae disease in different regions of Heilongjiang province,the conditions affecting the occurrence of rice bakanae disease and the chemical control technology were studied.The results showed that:1.After isolation and purification of bakanae disease samples collected from 5 different rice planting areas in Heilongjiang province,morphological and molecular identification,and pathogenicity determination were carried out.It was concluded that Fusarium fujikuroi and Fusarium proliferatum were the main pathogens causing rice bakanae disease in Heilongjiang province.The pathogenicity of the isolates collected from different areas was different,and the pathogenicity of the isolates collected from Qingan(QA)was the highest.2.Four kinds of inoculation treatments were tested on rice seeds.The results showed that the inoculation effects of different inoculation methods were different.Among the four kinds of inoculation treatments,the effect of spraying spore suspension on rice seeds was the best,and the incidence rate was 24.58%.The inoculation effect of soil mixed with sorghum grains with pathogen was the worst,the incidence rate of it was only 7.22%.3.The results of the effects of different conditions on the incidence of rice bakanae disease showed that the temperature of seed soaking and germination affected the occurrence of rice bakanae disease directly,and the incidence of rice bakanae disease increased with temperature.The infection rate of Fusarium fujikuroi was the highest when bud length is half-grain,and the suitable infection temperature was 32 °C during soaking and germination process.4.The inhibitory effects of 11 fungicides on Fusarium fujikuroi were determined by mycelial growth rate method,concave slide method and spore counting method.The results showed that 43% tebuconazole,20% pydiflumetofen,25% phenamacril and 25% prochloraz had better inhibitory effects on mycelial growth,sporulation and spore germination.Then the joint-toxicity of fungicide mixtures against Fusarium fujikuroi was evaluated.The results showed that when the volume ratio of 25% prochloraz and 20% pydiflumetofen was 1:1,the virulence of the mixture to the mycelium growth was the highest.The volume ratio of 25%phenamacril and 20% pydiflumetofen was 4:1,the inhibitory effect of the mixture to the sporulation of Fusarium fujikuroi is the best;when the volume ratio of 43% tebuconazole and20% pydiflumetofen is 1:1,the inhibitory effect on spore germination of Fusarium fujikuroi is the most obvious.5.The control efficacy of 25% phenamacril with 2000 times solution seed soaking is the best among seed soaking with single agent treatment.When the seed coating agent is coated alone,the control efficacy of 20% pydiflumetofen used at 0.25 m L per kg of seed is the most ideal.In the treatment of seed coating and seed soaking with agents,the control efficacy of the dosage of 3 m L seed coating agent per kg of seeds is coated with 11%sedaxane·fludioxonil·metalaxyl then soaked with 25% phenamacril with 4000 times solution is the best.When the two seed soaking agents are used in combination,the control efficacy of25% phenamacril with 2000 times solution and 43% tebuconazole with 3000 times solution is the highest when the mixing volume ratio is 1:1.