Studies on the Soil Fungicides.
I. Fungicidal Action of the Organic Mercury Compounds in the Soil.
1957 Volume 22 Issue 4-5 Pages 197-200
Details
1957 Volume 22 Issue 4-5 Pages 197-200
In the present study, the writers compared the changes of fungicidal activities of four organic mercury compounds, i.e., methylmercury iodide, ethylmercury phosphate, methoxyethyl mercury chloride, and phenylmercury acetate, after they were applied to soil. Ten ml. solution of each compound was applied 12g. soil. kept at 25°C. for 24 hours, and the fungicidal activity of the soil-organic mercury compound mixture was assayed on the plate culture of Ophiobolus sativus by the use of cup method. After this, the soil was washed with 10ml. distilled water, filtered through Toyo Filter paper NO. 2, and the fungicidal activity of the filtrate and that of soil residue were assayed by the same method. This procedure was repeated 8 to 14 times.
1. Methylmercury iodide-soil mixture had a fungicidal activity equal to that of the methylmercury iodide solution. After repeated washing with distilled water, the fungicidal activity of the soil residue decreased, but it still maintained a certain constant level (Fig. 2). This suggests that the compound. combines with soil particles without losing the fungicidal activity.
2. Methoxyethylmercury chloide-soil mixture showed a very low fungicidal activity. By repeatedly washing the soil with distilled water, the soil residue lost rapidly the fungicidal activity, but the filtrate maintaind a certain level of activity (Fig. 3).
3. Ethylmercury phosphate-soil mixture had a fairly high fungicidal activity. The fungicidal activity of filtrate and soil residue, obtained by washing the soil with water, decreased gradually with the repetition of washing (Fig. 4).
4. Phenylmercury acetate-soil mixture showed a very low fungicidal activity. The Soil residue and the filtrate, obtained by washing the soil with water, maintained a very low fungicidal activity, decreasing gradually with the repetition of washing.
Above results suggests that the Booer's hypothesis (1944) is true with the latter three compounds, but it is not true with methylmercury iodide.
