Abstract: The spatial distribution patterns and sampling technique of oilseed rape stem rot disease in oilseed rape crop Brassica campestris were surveyed and analyzed through index formulae, Taylor and Iwao regression formulations. The results showed that incidence of the stem rot was mainly in aggregation distribution, but the level of aggregation was low, and the spatial distribution patterns belonged to random and uniform distribution in few fields. In the low incidence of the disease, the spatial distribution pattern was inclined to random and uniform pattern. Theoretical sampling size decreased as quantity of infected plants of S. sclerotioum increased. In addition, the optimum theoretical sampling size of the infested rape plants could be obtained from the formula n2=103.33/m-0.86, in which m is the mean number of rot stems in a sampling unit (10 plants in a continuous growing line).

Key words: tem rot disease of rape, Sclerotinia sclerotioum (Lib.) de Bary, spatial distribution pattern, sampling technique