Spatial Pattern of Infected Plants and Sampling Methods of Asparagus (Asparagus officinalis) Stem Blight
The spatial pattern and sampling methods of asparagus (Asparagus officinalis) stem blight were studied in this paper.The results showed that the infected plants by the stem blight distributed at random in the newly-planted fields, but aggregated mainly in the fields where the asparagus had been planted for more than 3 years. Through the analysis of the index of spatial pattern, the infected plants attracted each other. The individual group was the basic composition of the spatial distribution. The research results also revealed that there was no correlation between the aggregation and the rate of infected plants, The reason for that type of distribution could be relative with the infection and spread of the blight disease. Different sampling methods were observed in the fields, and sample of tessellated type was the best, secondly the sample of diagonal type.The theoretic sampling number was given at different rates of infected plants.