褐飞虱(Nilaparvata lugens)发生的分形性质研究

运用分形理论以安徽省庐江县植保站和江苏省吴县值保站1979～1990年及太湖地区农科所1986～1998年间褐飞虱发生的田间系统调查资料为例，对褐飞虱发生的性质进行了探讨。结果表明：(1)庐江站、吴县站和太湖地区农科所褐飞虱发生在一定标度域内具有分形性质。其分维值分别为0．7158、0．52l2和0．2816;(2)褐飞虱发生的分维值是表征一定标度区间的发生程度差异的一个新的参数，分维值大,则发生程度轻,反之则重(3)分维数D值与褐飞虱发生的聚集程度是密切相关的，D值小聚集程度大，反之聚集程度小，D值可以作为褐E虱聚集分布程度的一个指标；(4)褐飞虱发生具有多重分形结构，其广义维数谱Dq曲线可以用于褐飞虱发生的预测预报。

Study on fractal property of Nilapravata lugens(BPH) occurrence

The nature of BPH occurrence was investigated by means of fractal theory based on the systematic field investigation data of BPH occurrence.The results indicated:(1)BPH occurrence had a fractal property in fixed scale interval with the D value 0 7158,0 5212,0 2816 respectively.(2)The fractal dimension value of BPH occurrence was a new paramater expressing the distinction of occurrence degree in fixed scale interval,and the greater the fractal dimension value,the lighter the BPH occurance,and vice versa.(3)As D value showed a close correlation with aggregation degree,it could be used as an index for aggregation degree.(4) BPH occurrence possessed multifractal structure,and the related D q curve may have an application in the forecast of BPH occurrence.