应用马尔可夫链理论对褐飞虱和白背飞虱发生程度的预测

褐飞虱Nilaparvata lugens (Stál)和白背飞虱Sogatella furcifera (Horváth) 是我国稻区的主要迁飞性害虫,给水稻生产带来严重危害.以重庆市秀山县1983～2007年田间褐飞虱和白背飞虱发生程度的时间序列资料,运用基于马尔可夫链理论的转移概率预测法,构建了1～5阶转移概率矩阵,根据每一阶概率矩阵单独进行回报的历史符合率计算各阶转移概率矩阵的权重,以预报年前5a褐飞虱和白背飞虱的连续发生状态预测第6年的发生级别.回报20a的结果历史符合率均达到90%,对2008年的预测也符合当年田间实际发生情况.该方法构建的5阶转移概率矩阵及其权重对于秀山县及其邻近地区褐飞虱和白背飞虱发生程度的长期预报具有重要指导意义,为害虫的长期可预测性提供了一种快速、有效的方法.

Forecasting the occurrence degree of brown planthopper and whitebacked planthopper by applying Markov model

Brown planthopper, Nilaparvata lugens (Stal) and whitebacked planthopper Sogatella furcifera (Horváth) are two important long-distance migration insect pests that cause great losses to rice yield in China. In this paper, by using the transition probability method of Markov chain theory, the transition probability matrix of 1 to 5 steps was constructed based on the time series data of two planthoppers surveyed in rice paddy from 1983 to 2007 in Xiushan county, Chongqing, China. The weight of every step by the rewarding accuracy of each step in transition probability matrix was calculated and the occurrence degree of the sixth years was predicted based on the occurrence status of the previous 5 consecutive years. The result showed that history rewarding accuracy was 90% for the 20 years data from 1988 to 2007 and it accorded with the occurrence situation in 2008 for the both pests completely. The transition probability matrix and the weights constructed in this study have great guiding significance to forecast the occurrence grade of the two planthoppers for Xiushan and its neighboring areas. It offers a rapid and effective method for the long-term or the super-long term predictability of the pests.