Effects of nitrogen and organic fertilization on corn smut (Ustilago maydis (DC) Corda.)

Corn smut caused by Ustilago maydis occurs wherever conditions are suitable. Corn smut damages plants and reduces yields by forming galls on different parts of plants, including ears, tassels, stalks, and leaves. It has not been known yet that any fungicide is effective against corn smut. Therefore, it is very important to be able to control the disease through different means. One of the effective means is proper and balanced fertilization by taking into account uptake of the elements from soil by corn. This cultural practice is very important for control of corn smut. In the experiments in which effects of nitrogen fertilization on U. maydis were investigated, disease severity increased both when nitrogen was added at a higher dose than the recommended dose (100 kg ha(-1) (N1)) for the trial area and nitrogen was not used, whereas tolerance to the disease increased in the experiments with organic fertilizers in which different amounts of the barnyard manure was applied. Adjustment of amounts of nitrogen and farmyard manure seemed to be an important factor impacting the severity of corn smut disease in the field.