玉米纹枯病周期性脉冲Logistic模型研究

Study on Impulsive Logistic Model with Periodicity for Corn Sheath Blight

以郑单958、辽单565和丹玉39为试材接种玉米纹枯病菌,对玉米纹枯病的流行动态进行系统调查,应用SPSS11.5软件将3年数据进行分析拟合。结果表明,与Logistic模型相比,脉冲Logistic模型可更直观、明确地反映年度间玉米纹枯病的周期性流行动态情况且符合该病发展的生物学意义;通过脉冲Logistic模型可以发现,年度间同一品种玉米纹枯病的最大病情指数(KN)和初始病情指数(dN)存在较大差异,表观侵染速率(rN)的差异较小;经Lo-gistic模型推导,明确沈阳地区玉米纹枯病指数增长期为玉米出苗至7月上旬,逻辑斯蒂增长期为7月上旬到8月末或9月初,衰退期为8月末或9月初到玉米生育后期。

Corn sheath blight was studied by artificial inoculation in experimental fields, and the epidemic dynamics was systematically investigated from 2007 to 2009. Based on analyzed and fitted dates by SPSS11.5. The results showed that impulsive logistic model with periodicity could more intuitively and definitely reflect the simulation on epidemics of corn sheath blight than logistic model among years, and also according to its biological significance. According to the impulsive logistic model, there were great differences in the max and initial disease index among years, but there was little difference in the apparent infection rates. Logistic model deduced that exponential phase of corn sheath blight was from seeding stage to begin July in Shenyang, the logistic phase was from begin July to late August or early September, the decline phase was late August or early September to the end of corn grow stage.