Fungicide control ofUstilago bullataseedling and shoot infection ofBromus catharticus

Abstract

Abstract Fungicide control of Ustilago bullata Berk. seedling and shoot infection of Bromus catharticus Vahl was investigated in glasshouse trials. Seedling infection was controlled adequately with 2,3-dihydro-6-methyl-5-phenylcarbamoyl-l,4-oxathiin (carboxin) and tetramethylthiuram disulphide (thiram) at rates of 3 and 12 g active ingredient (a.i.)/kg seed respectively, without reducing seedling emergence from soil using freshly treated seed, or germination of treated seed after 6 months' storage. Methyl-l-(butyl-carbamoyl)-benzimidazol-2-yl-carbamate (benomyl) at 3 g a.i./kg seed gave good control of seedling infection, but slightly reduced seedling emergence. Shoot infection was controlled with soil drenches of benomyl and carboxin but at rates (40 kg a.i./ha) that were likely to be uneconomic in practice. Five other fungicides, including N-trichloromethyl-thio)-3a,4,7,7a-tetrahydrophthalimide (captan), 2-(4-thiazolyl) benzimidazole (thiabendazole), the 4,4 dioxide of carboxin (oxycarboxin), and two ex...