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Rice foot rot is the most important seed-borne disease of rice. The efficacy of Tachigaren fungicide at three doses 1/1000, 1.5/100 and 2/1000 compared with triflumizole® and the control treatment in controlling rice foot rot was investigated in the laboratory and nursery of the Rice Research Institute of Iran in Amol and Rasht in 2018. According to the company recommendation, rice artificial infected seeds with the pathogen were treated for 20 minutes in a solution of Tachigaren with the mentioned doses. The experiment included five treatments, four replications and was carried out in a completely randomized and completely randomized block design in the laboratory and nursery, respectively. Result showed that Tachigaren fungicide was not sufficiently effective in controlling the pathogen. Therefore, new treatments were carried out to investigate the efficacy of this fungicide in laboratory conditions. The results showed that the lowest percentage of disease was observed in the seed disinfection treatment with 2/1000 solution of the Tachigaren fungicide for 18 hours. Seed disinfection treatments with Tachigaren fungicide at a dose of 2/1000 for 18 hours, triflumizole, control treatment with artificial contamination, and control without artificial contamination were conducted in Mazandaran and Guilan rice nursery conditions in 2019. The experiment included four treatments, four replications, and was conducted in a randomized complete block design. The number of diseased, dead, and healthy seedlings, seedling height, root length, and fresh and dry weights of seedlings and roots were determined. The effect of Tachigaren at different doses on mycelial growth of Fusarium was also investigated in comparison with the control fungicide in laboratory conditions. Data were analyzed using SAS software. Result of ANOVA test showed that the effect of treatment was not significant for the percentage of healthy seedlings in the laboratory and the nursery of Amol and Rasht in 2018. Comparison of means showed that disinfection of artificial infected seeds with Fusarium with the Tachigarne fungicide for 20 minutes had no effect on disease control in laboratory (Petri dish) and nursery compared to the control without fungicide, but the control Triflumizole fungicide was effective. In re-examination of the efficacy of Tachigaren in laboratory conditions, the lowest percentage of disease was observed in seeds that were soaked in 2/1000 solution of Tachigarne for 18 hours The results of this study also showed that the percentage of seed germination decreased with increasing dose of Tachigaren. Result of ANOVA test showed that the effect of treatment was significant for percentage of healthy, diseased, and dead seedlings in the nursery of Amol and Rasht in 2019. Comparison of means showed that the efficacy of Tachigan fungicide in producing healthy seedlings was better than triflumizole and was placed in a higher group, but it was placed in a lower group than the control treatment, and the percentage of healthy seedlings was less than 80%, which is not desirable.Also, percentage of healthy seedlings in control treatment with artificial inoculationwas high, indicating low pathogenicity of the pathogen. Therefore, the results of this experiment need to be repeated.Result of ANOVA test showed that the treatments had a significant effect on the growth rate of Fusariumon PDA medium in Petri dishes and under controlled conditions.Comparison of means showed that Tachigaren fungicide reduced the growth rate of Fusarium in Petri dishes compared to the control, but was less effective compared to the two fungicides Triflumizole and Nordox, and was placed in the lower group in terms of the percentage of growth control of Fusarium.Therefore, the efficacy of this fungicide for controlling Fusarium is not acceptable and cannot be recommended. This experiment showed that the two fungicides, Triflumizole and Nordox, are effective on Fusarium, the cause of rice foot rot disease, and are still recommended.Overall Tachigaren was not sufficiently effective in controlling rice foot rot disease by soaking seeds methode in fungicide solution.
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