利用碳酸氫鉀與聚電解質防治作物白粉病

Abstract

測試0.5、1.0 及2.0% (w/v) 碳酸氫鈉、碳酸氫鉀及碳酸氫銨等三種重碳酸鹽對番茄白粉病菌(Oidium neolycopersici)、豌豆白粉病菌(Erysiphe pisi) 及玫瑰白粉病菌(Sphaerotheca pannosa)等孢子發芽的影響，發現均可有效降低孢子發芽率，其中以碳酸氫鈉與碳酸氫鉀的效果最佳，且在0.5% (w/v) 時即可表現顯著(p<0.05) 的抑菌效果。以切離葉測試重碳酸鹽類與聚電解質FO4490SH 抑制番茄白粉病的效果，顯示0.5% (w/v) 碳酸氫鈉、碳酸氫鉀與0.03% (w/v)FO4490SH 均可有效降低白粉病的發生，其中以前兩者的抑病效果最明顯，而碳酸氫銨則無法有效降低白粉病。田間測試0.5% (w/v)碳酸氫鉀、0.03% (w/v) 聚電解質FO4490SH、二者混合液及化學藥劑等對番茄、豌豆及玫瑰白粉病的防治效果，發現碳酸氫鉀、碳酸氫鉀與聚電解質混合均可有效降低白粉病的發生，防病效果與化學藥劑之間呈不明顯差異(p > 0.05)，三者的防治率均達83.2% 以上；而聚電解質的抑病效果則較其他三種處理的效果為差，且聚電解質與碳酸氫鉀混合液並未能增進病害防治效果。由豌豆白粉病的田間試驗發現，噴水處理亦具有抑制白粉病的效果，與對照不噴水處理之間呈顯著差異(p < 0.05)。綜合三個田間試驗結果，顯示0.5%(w/v) 碳酸氫鉀的防病效力與化學藥劑無異，可推荐給農民使用。 Sodium bicarbonate, potassium bicarbonate and ammonium bicarbonate were evaluated for their inhibitory effect on spore germination of three powdery mildew pathogens, Oidium neolycopersici, E rysiphe pisi, and S p h a e rotheca pannosa. Data showed that the spore germinations of these pathogens were significantly (p<0.05) suppressed by all three bicarbonates, especially sodium and potassium bicarbonate at 0.5% (w/v). Detached leaf method also was used to evaluate 0.5% (w/v) bicarbonates and 0.03% (w/v) polyelectrolyte (FO4490SH) for control of powdery mildew. The result showed that all treatments except ammonium bicarbonate reduced the infection area of powdery mildew on tomato leaf surfaces, especially sodium and potassium bicarbonate. Three field trials were conducted in central Taiwan to evaluate the applicability of potassium bicarbonate, polyelectrolyte and fungicides for control of tomato, pea and rose powdery mildew. Each trial was arranged in a completely randomized design with four replications. Potassium bicarbonate at 0.5%, and 0.5% potassium bicarbonate plus 0.03% polyelectrolyte were effective in decreasing the disease severity of powdery mildews on all three crops tested. The treatments were as effective as fungicides. The percentages of disease control in all three treatments were more than 80%. The severity of powdery mildew was only slightly reduced by the treatment of polyelectrolyte alone on tomato and pea. Polyelectrolyte did not increase the efficacy of disease control by potassium bicarbonate in this study. Spray with water also slightly reduced the disease severity of powdery mildew on pea in comparison with no water spray. This study showed that 0.5% potassium bicarbonate could be used as an alternative method for control of powdery mildew in the field.