水稻紋枯病之系統性藥劑室內及田間防治試驗

Abstract

本試驗係為尋求系統性殺菌劑，以解決防治稻紋枯病藥劑操作上之困難，所得結果簡述如下： 在室內測定幾種藥劑之預防及治療效果，結果以Benlate水和劑每盆400倍液灌注20ml區（每公頃13.2公斤）及10ml （每公頃6.6公斤）區之效果最佳，不過按此施藥量對紋枯病之防治固有效果，但其價格昂貴，在實用上藥劑費用似嫌過高。在預防方面，Tachigaren液劑和Mon乳劑之防治效果略相同；但治療方面 Mebenil水和劑，Tachigaren液劑和Mon乳劑等藥劑，自接種病原菌後施藥愈遲其防治效果愈差。 應用有機砷劑防治稻紋枯病時，其使用時期於水稻抽穗期10天以內似應避免施用，以及不可隨意提高使用濃度，以避免藥害之發生。 田間試驗結果，一般說來預防比治療之防治效果良好，對紋枯病之防治效果以Benlate 水和劑最佳，無論使用方法為灌注或秧田土壤處理皆有良好的效果，同時亦有防治稻小粒菌核病之功效。 This experiment is aimed at searching systemic fungicides for control of rice sheath blight in order to solve the problem of the practical difficulties of using fungicides spray. In greenhouse trials, Benlate W.P. showed the remarkable preventive and therapeutic effect when 20 ml. of 1:400 solution (13.2 Kg/ha) or 10 ml. of 1:400 (6.6 Kg/ha) solution of Benlate were added to the pots, 22 cm in diameter, respectively. However, the application of such fungicide at the rate of 13.2 Kg/ha or 6.6 Kg/ha seems to be too expensive for practical use in controlling the disease. In preventive effect, Tachigaren Solution and Mon Emulsion were similar in effectiveness of controlling the disease. But in case of therapeutic action, fungicides of Mebenil W.P., Tachigaren Sol. and Mon Emul. showed that the later the application after inoculation of pathogen, the less control effect to the disease. For the prevention of phytotoxicity, the application of organo-arsenate shouldn’t less than 10 days before heading stage and the rate applied shouldn’t higher than the recommended concentration recorded in the Extension Manual. Among the four fungicides tested in the field, Benlate W.P. was the best one in controlling the disease either by adding to the field soil or treating the seedling soil. Simultaneously, it also showed the effectiveness in controlling the disease of rice stem rot.