A Detailed Explanation of the Orchid Fungicides Thiophanate and Thiophanate-Methyl

Both thiophanate and thiophanate-methyl are new, highly effective, low-toxicity, broad-spectrum systemic fungicides. The former has the chemical name 1,2-bis(3-dioxycarbonyl-2-thiosulfonylurea)benzene, and the latter has the chemical name 1,2-bis(3-methylcarbonyl-2-thiosulfonylurea)benzene. The pure products are both colorless flaky crystals, while the technical-grade products are white or pale yellow solids, poorly soluble in water, chemically stable, and of low toxicity to humans and livestock. In terms of formulations, thiophanate is available as a 50% wettable powder; thiophanate-methyl is available as wettable powders in two concentrations, 50% and 70%. Spraying a 500-1000 times dilution of thiophanate 50% wettable powder can controlorchids, roses and other ornamental flowers and trees against multiple diseases. The efficacy of thiophanate-methyl is 1/3 to 1/2 higher than that of thiophanate, so the dilution factor should be appropriately increased when using it. Points to note when using: (1) It can be mixed with many pesticides and alkaline pesticides such as lime sulfur mixture, but it should not be mixed with copper-containing preparations; (2) After application, the liquid adhering to the skin should be washed off with water to ensure safety. (Liu Zhongjian, Xu Gongming)