西兰花根肿病空间分布型及抽样技术研究

摘要

[目的]进一步提高对西兰花根肿病预测预报与持续控制能力。[方法]应用最小二乘法、频次分布、聚集度指标、m*-m回归分析和 Taylor幂法则等对病株的空间分布型进行了分析。[结果]西兰花根肿病病株田间分布趋向于聚集分布。 m*-m回归分析表明病株空间分布的基本成分是个体群，病株个体间相互吸引；病害在大田中存在明显的发病中心，个体群在田间呈均匀分布格局，即分布的基本成分个体群之间趋于均匀分布。 Taylor幂法则分析表明，西兰花根肿病病株个体的空间格局随着病株密度的提高越趋均匀分布。在此基础上，提出了 Iwao最适理论抽样模型 N=273.9541/m-59.6985，并建立序贯抽样模型T0（N）=0.3684N±1.9268姨N ，即：调查株数 N时，若累计发病率超过上界可定为防治对象田，若累计发病率未达到下界时，可定为不防治田，若累计发病率在上下界之间，则应继续调查，直到最大样本数 m0=0.3684时，也即发病率15%，所需抽样数684株。[结论]该研究结果对于病害防治具有十分重要的指导意义。%Objective] To further improve the prediction and forecast and continuous control ability of broccoli clubroot disease. [Methods] The spatial distribution pattern of diseased or infected plants was analyzed using the least square method, fre-quency distribution, aggregation index, m*-m regression analysis and Taylor’s pow-er law model. [Result] The field distribution of broccoli plants with clubroot disease tended to be aggregated distribution. m*-m regression analysis showed that the el-ementary composition of the spatial distribution of diseased or infected plants was individual colony, the individuals attracted each other; the disease had obvious dis-ease focus in the field, and the individual colony showed uniform distribution pattern in the field. Taylor’s power law showed that the spatial pattern of individual dis-eased or infected plant with clubroot disease tended to be uniform distribution with the increase of the density. On the basis of this, Iwao optimal theoretical sampling model and sequential sampling model were established, namely N =273.954 1/m-59.698 5, T0 (N)=0.368 4N±1.926 8√N , respectively, it meant that when surveying N plants, if the accumulative incidence rate exceeded upper bound, the field can be set as control object; if the accumulative incidence rate didn ’t reach lower bound, it can be set as uncontrol field; if the accumulative incidence rate was between upper bound and lower bound, it should be surveyed continuously until the maximum sample size (m0=0.368 4) appeared, that was, the disease incidence was 15%, so the sampling number should be 684 plants. [Conclusion] The research results had very important instructive meaning for disease control.