利用幼虫粪粒数制定防治指标的研究

１９９２～１９９５年经过对枣步曲排粪规律、食叶量、枣树蓄叶量以及不同失叶水平对枣果产量影响的系统研究，建立了排粪量与平均气温的数量模型：Ｆ∧＝０．５６２９＋０．０１６２Ｔ，枣树蓄叶量估测模型：株蓄叶总面积＝株总枣股数×每股平均枣吊数×每吊平均枣叶数×平均枣叶面积，单位树冠面积下单位时间落粪粒数动态防治指标模型：Ｙ＝（２２６．１９４Ｘ３－３７３．７５４６）Ｘ－２３（０．５６５９＋０．０１６２Ｔ），经林间验证，准确度在９０％以上。

Studies on Determining Control Action Threshold by Frass drop Amount of Sucra jujuba

From 1992 to 1995,systematic studies had been made on the frass-drop amount and leaf eating amount of Sucra jujuba, the leaf yield of jujube tree,and the influences of different leaf losing levels on fruit output of jujube trees. The mathematic model of frass-drop amount and average temperature,the estimatic survey model of leaf yield of jujube tree,and the dynamic control action threshold model according to frass-drop amount in per time and per area were set up as: F=0.562 9+0.016 2T,(Total leaf yield area)=(total spur of jujube)×(average jujube deciduous spur of per spur)×(average leaves of per jujube deciduous spur)×(average leaf area), Y=(226.194X₃-373.754 6)X₃^-2(0.565 9+0.016 2T)respectively.The results of field examinations showed that the accuracy of all these models was over 90%.