Effective control of barley leaf blotch with funcicides
1989
Volk, T. (Institut fuer Pflanzenschutz, Saatgutuntersuchung und Bienenkunde, Muenster (Germany, F.R.)) | Frahm, J.
Spores of Rhnychosporium secalis (comparable to Septoria tritici) are transported to the upper leaves by rain-splash. During the growth stage 'stem elongation' the important infections occur on the youngest, folded leaf and on older leaves at the leaf axil. This depends on the favoured environment conditions at these sites. Because of the latent period of nearly 190 degrees C-days (basis 0 degree C) and the temperature sum of nearly 75 degrees C for the growth of a barley leaf the two youngest leaves are always apparently disease free during shooting. In field trials and a glasshouse test preinfection applications of the 8 tested fungicides failed. The curative efficacy was best for the fungicide Flusilazol (160 g a.i./ha), up to 11 days after inoculation. The fungicides Tebuconazole, Prochloraz, Propiconazole and the still in Germany not available Flusilazol allow an effective control of barley leaf blotch, but the timing of the application is critical, only a few days after a prolonged period of rainfall which includes the necessary rain-splash high degrees of efficacy are possible
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