Abstract: This paper deals with the spatial pattern indices for biological population based on Pearson's Ⅲ type distribution and exponential distrbution. The results show that their precision is higher than that of classical frequency distributions. The judging indices of aggregation and formula for required number of sampling in the case of Pearson-Ⅲ distribution and exponential distribution are presented and successfully used in analysis of the spatial pattern and sampling number for inoculum source of wheat scab. Finally, advantages of the continuous models in application to spatial pattern are discussed.

Key words: Pearson-Ⅲ type, Exponential distribution, Spatial pattern, Wheat scab