Abstract: The development and damage of rice sheath blight are affected by such factors as rice strain,amount of applied fertiizer N, meteorological factors, damage loss, incidence time, seriousnessdegree of the disease and chemicals, which were studied quantitativcly with continuouslycropped early rice as test crop. The results indicated that different rice strains showed differentlevels of resistance and damage loss. The seriousness degree of the disease was closely correlatedwith the amount of applied fertilizer N, and the prevalent speed was clasely related to the average daily temperature and rainy day frequency. The relationship between incidence time anddamage loss was no significant, and the effect of chemicals was correlated with control timeand disease index.

Key words: Rice sheath blight, Prevalence, Damage