Key points
- In the last four years, wet weather has caused head bleaching and seed yield losses of up to 70% in cocksfoot crops, threatening the viability of the industry in parts of Canterbury.
- The cause of these symptoms has been identified as downy mildew, a disease caused by an oomycete pathogen.
- Oomycetes are difficult to control, but in recent fungicide trials, seed yields were increased three-fold with treatments that had either Bravo® (a.i. chlorothalonil, mode-of-action Group M5) and Phoenix® (a.i. folpet, Group M4).
- The addition of a triazole (Proline®) to Bravo® increased seed yield response by 23%.
- The use of triazole, strobilurin and SDHI fungicides alone, or in a mixture, increased seed yields by 50% (triazole only) to 100% (triazole + strobilurin + SDHI) above the untreated control.
- Overall, these data suggest a disease complex may be responsible for recent seed losses in cocksfoot.
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