The fungicides efficacy against Fusarium graminearum, Fusarium culmorum and Microdochium nivale in in vitro conditions

In presented work, the problem of selective fungicide efficacy against selected Fusarium species was evaluated. The aim of work was to study the level of fungicide seed treatment efficacy against the most important Fusarium species in in vitro conditions. The fungicide seed treatment efficacy was tested by winter wheat kernel germination in 100% pathogenic microenvironment of selected fungi Fusarium graminearum (strain 399), Fusarium culmorum (strain 418) and Microdochium nivale (strain 401). The strains were cultivated on potato-dextrose agar at 21 deg C and 12/12 photoperiods. After the whole culture surface colonisation by the species, the fungicide treated and untreated wheat kernels were placed on the surface of pathogenic medium of each strain. The wheat kernels were germinated by the same cultivation condition as culture incubation. For seed treatment, the following seven fungicides were used: quazatine, tebuconazole/thiram, tebuconazole, carboxin/thiram, difenoconazole, iprodione/triticonazole, bitertanol/fuberidazol. On the tenth day after seed placing on agar medium the germination of grains, infestation of roots, sprouts infection and weight of created biomass were measured. The obtained results were tested by analysis of variance and Tukey test at P = 0.95. The highest reduction of germinating kernels was observed in pathogenic microenvironment of F. graminearum, followed by F. culmorum and M. nivale. The weight of created biomass is considered as the best general indicator of fungicide efficacy against all forms of Fusarium diseases on germinating kernels. According to this indicator, the general efficacy of fungicides was measured in the following downward order: against F. graminearum: bitertanol/fuberidazol, tebuconazole, quazatine, carboxin/thiram, tebuconazole/thiram, difenoconazole, iprodione/triticonazole against F. culmorum: bitertanol/fuberidazol, tebuconazole, quazatine, difenoconazole, tebuconazole/thiram, iprodione/triticonazole, carboxin/thiram against M. nivale: quazatine, carboxin/thiram, tebuconazole, tebuconazole/thiram, difenoconazole. Comparing the highest fungicide efficacy against each pathogen, there is not possible to choose the universal and the most effective fungicide with general efficacy against all evaluated Fusarium pathogens. It is necessary to evaluate separately the fungicide efficacy against each pathogen and the choice of the most effective fungicide requires appreciating according to the prevalent pathogens in the seeds.