Efficacy of three systemic fungicides against the downy mildew of corn, Sclerospora maydis (Racib.) Butler in Indonesia
1980
Molina, R.P. (Gregorio Araneta Univ. Foundation, Malabon, Metro Manila (Philippines))
This study was conducted at Central Research Inst. for Agriculture (CRIA), Bogor, Indonesia evaluated the protective and curative effect of three systemic fungicides, ridomil(methyl D, L-N-(2,6-dimethyl-phenyl)-N-(2 methoxyacetyl)-alaninate), aliette (aluminum tris-O-ethyl phosphate) and terrazole (5-ethoxy-3-trichloromethyl-1, 2, 4-thiadiazole) against downy mildew (DM) of corn. The fungicides were applied as seed and soil treatments, and foliar sprays at various dosages. Based on vitro tests, ridomil inhibited 50% spore production of the fungus at 50 ppm/a.i.; aliette at 100 ppm and terrazole at 500 ppm/a.i. Ridomil showed excellent systemic effect in all treatments (dipping whole leaf, basal leaf and leaf tip) as compared with the two other fungicides. As seed treatment, ridomil proved highly protective than aliette and terrazole. Terrazole was the least effective among the fungicides tested. When applied as soil treatment, ridomil significantly protected the corn plants against DM infection for 42 days, while terrazole only give fair protection. As foliar sprays, aliette was more protective than terrazole and dithane. Infected plants observed for 50 days at 10-day interval after each spray application for curative effect showed that ridomil was more curative compared to aliette and terrazole. Dithane sprayed plants never recovered from the disease. Complete recovery from the disease were observed only in the ridomil treated plants.
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