褐飞虱发生系统的混沌诊断

褐飞虱在我国常年发生面积约为1．3×10^7～2×10^7hm^2，年均损失稻谷10×10^8kg．为更深入地研究褐飞虱发生系统的特性与规律，并为预测和防治提供理论依据，以我国长江流域太湖地区1986～1998年6～11月褐飞虱田间发生时间序列资料为例，运用混沌理论中的自相关函数、功率谱图、相轨迹图、Poincare截面、返回映象图等方法，研究了褐飞虱发生系统的特性．结果表明，即使有随机性噪声的影响，仍可判明我国长江流域褐飞虱发生系统具有混沌特性．

Chaotic diagnosis of Nilaparvata lugens occurrence system

It is estimated that there are nearly 20 million hectares of rice crop being infested by Nilaparvata lugens , with an annual loss of some half a million tones of grain. In order to study the properties and laws of Nilaparvata lugens occurrence system further, the time series data of Nilaparvata lugens occurrence from 1986 to 1998 collected in Taihu Lake District were analyzed by using the methods of autocorrelation function, power spectrum figure, phase trajectory figure, poincare section, and return map of chaos theory. The results indicated that Nilaparvata lugens occurrence system in Yangtze River valley area in China had an obvious chaotic property, even though there was some interference of random noises.