STATUS OF RICE FALSE SMUT (Ustilaginoidea virens) DISEASE IN FOUR UNIONS OF NATORE DISTRICT IN BANGLADESH

Abstract

Rice false smut has become an emerging disease across the world. Its incidence has become serious in Bangladesh during T. Aman season in the last five years. However, the actual level of incidence of the disease in the farmer’s field has not been estimated in this country. This study included a field survey during ripening stage of T. Aman rice in four unions of Natore district in order to estimate the disease incidence, number of smut balls per infected panicle and yield loss, and to ascertain effectiveness of farmer’s fungicide application. The results show that across the four unions, disease incidence, number of smut balls per infected panicle and yield loss were 8.06±2.02%, 2.88±0.17 and 0.72±0.18% (± is 95% confidence interval), respectively. Disease incidence (18.71±5.18%), number of smut balls per infected panicle (3.51±0.39) and yield loss (1.75±0.38%) was the highest in Ramananda Khajura union compared to the other three unions. Among the varieties, BRRI dhan49 incurred the highest disease incidence (18.71±5.18%), number of smut balls per infected panicle (3.51±0.39) and yield loss (1.75±0.38%) than others. The crops which flowered during mid-October to end November showed significantly higher disease incidence than early flowering crops. Fungicide application tended to have reduced the disease, but did not show significant difference with no fungicide application. It is concluded that the strategic management of the disease may be directed specific of the fields where there is a history of the disease through manipulating genotypes and transplanting time. The tactical management of the disease by using fungicides needs to be comprehensively investigated (with respect to products, rate, frequency and timing of application) to ascertain its effectiveness under farmers’ field conditions.