Effects of Silicon, Copper and Zinc Applications on Sheath Blight Disease Severity on Rice

Rice (Oryza sativa L.) sheath blight disease is one of the most important diseases globally which makes its management very difficult. Severe soil micronutrients deficiency and high dosage of nitrogen fertilizer leading to the development of sheath blight disease has become a constraint in rice production in Malaysia. The study was conducted to compare between MR219 and MR253 rice varieties to sheath blight inoculations and micronutrient applications and to determine the impact of disease on rice yield. Sheath blight epidemics in pots were initiated by inoculation at maximum tillering growth stage under glasshouse conditions in April 2013. Silica gel, copper sulphate and zinc sulphate were applied to the soil prior to planting at the rates of 360g, 0.30 g, 0.45g per 15 kg soil respectively. Inoculation significantly (P=0.05) increased sheath blight severity and incidence which caused yield losses of 11% in moderately resistant variety MR219 and 50% in moderately susceptible variety MR253. Micronutrients application reduced sheath blight incidence and severity regardless of varieties. Fertilization with Si was significantly more effective than Cu and Zn treatments in minimizing yield loss due to sheath blight in both varieties.