Glasshouse evaluation of fungicides for the control of sunflower downy mildew (Plasmopara halstedii)


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A precise, reproducible and easy‐to‐handle glasshouse test is described for the evaluation of the systemic activity of chemicals for the control of Plasmopara halstedii, the downy mildew pathogen of sunflower. Four‐day‐old sunflower germlings were inoculated by immersing them in a zoosporangium suspension. Seedlings were then immersed in appropriate concentrations of the chemicals to be tested. Plants were grown in a glasshouse and assessed on three occasions to determine successively antisporulant, curative (systemic fungistatic), and eradicant effects. Sporulation in general was inhibited by lower concentrations than those required to exert an eradicant effect. There was a highly significant correlation between the ED50 values for visually recognised disease symptoms (stunting, dampingsff and leaf chlorosis) and for both curative and eradicant effects. Among 13 compounds tested, metalaxyl, RE 26745, furalaxyl, LAB 149202F and cymoxanil showed sufficient eradicant activity, to justify field evaluation for eradication of seed infections.

Original languageEnglish
Pages (from-to)53-63
Number of pages11
JournalAnnals of Applied Biology
Issue number1
Publication statusPublished - 1987


ASJC Scopus subject areas

  • Agronomy and Crop Science

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