Original scientific paper
Changes of species spectrum associated with Fusarium head blight caused by fungicides
2019, 20 (1) p. 376-388
Fusarium head blight (FHB) is a dangerous disease of cereals in case of yield losses and mycotoxin production. The aim of this work was to estimate the influence of used fungicides on species spectrum associated with Fusarium head blight (FHB). The study was realised in Slovakia on winter wheat by natural infection of FHB. The ears were sprayed with fungicides at beginning of flowering. After development of disease symptoms, fungicide efficacy was estimated, and Fusarium species spectrum were isolated and determined in laboratory. The fungicide efficacy against FHB achieved 60.2 – 88.3 %. The highest effectivity was estimated by using of prothioconazole + tebuconazole and prothioconazole + fluoxastrobin, followed by dimoxystrobin + cyproconazole, metconazole, propiconazole + cyproconazole, and prochloraz + tebuconazole. F. graminearum was the most frequently isolated from the ears, followed by M. nivale, F. avenaceum, F. culmorum, and F. poae. Using of prothioconazole + tebuconazole, metconazole, prothioconazole + fluoxastrobin, and tebuconazole significantly decreased incidence of F. graminearum on infected ears. The incidence of M. nivale on ears was significantly increased by using of all fungicides in comparison with untreated control. The results suggest that the ear spraying by triazole fungicides could enhance the incidence of less susceptible Fusarium species in ears, especially M. nivale. The variability in fungicide efficacy of fungicides against FHB in agricultural praxis colud be affected besides multi-pathogen origin of FHB just by selective effect of fungicides on different Fusarium species.