ISSN 1392-3196 / e-ISSN 2335-8947
Zemdirbyste-Agriculture, vol. 109, No. 2 (2022), p. 149–156
Evaluation of fungicide application programmes for Septoria tritici blotch control in winter wheat
Karolina VERIKAITĖ, Jūratė RAMANAUSKIENĖ, Rita ARMONIENĖ, Antanas RONIS
Zymoseptoria tritici is the causal agent of Septoria tritici blotch (STB) in wheat, and its spread is reported to depend on environmental conditions. Since the spread of disease is usually controlled by using fungicides, selecting timings of their application is crucial. The aim of the present study was to estimate the effect of two fungicide application programmes for STB control in winter wheat and to evaluate the relationship between the severity of disease and quantified DNA of Z. tritici in leaves. Two field experiments (in monoculture field and in the field after non-host crops) with winter wheat were designed, and six fungicide application treatments were chosen. For the disease control, fungicide Adexar (a.i. fluxapyroxad 62.5 g l-1 + epoxiconazole 62.5 g l-1) in dosages 1.0 and 2.0 l ha-1 was used. In 2019, due to unfavourable meteorological conditions, plant infestation with the pathogen was low. Nevertheless, comparing the experiments from both crop rotations, there were marked trends of higher severity of STB in winter wheat monoculture. Meanwhile, in 2020 and 2021, the values of the area under the disease progress curve (AUDPC) were higher in winter wheat grown after non-host crops. Differences between tested application programmes were more precise at higher disease pressure in 2020 and 2021. According to the results of a three-year field experiment, higher effectiveness of controlling STB showed fungicide application programmes based on weather conditions and two applications per season. A more important influence of fungicide application programmes on grain yield increase was found in winter wheat monoculture. Application of fungicides had a higher impact in the 2020 cropping season, when a higher level (AUDPC 358.6) of STB disease infection was observed. In both crop rotations, the highest grain yield increase was obtained by applying fungicide twice: 8–10 days after rain and two weeks after the first application. In both crop rotations, Pearson’s correlation test showed a strong relationship between visual assessments of disease severity and DNA quantity of Z. tritici in leaves of winter wheat.
Keywords: application programmes, AUDPC, real-time-PCR, Septoria tritici blotch, Zymoseptoria tritici.