一种求解病虫害防治指标的新模型

根据经济阈值定义的模式“挽回收益＝ 防治成本”及公式“挽回减产率＝ 对照减产率－ 防治区减产率”，提出了一种求解病虫害防治指标的新模型。若病虫害为害量（ｘ）与作物产量损失率［ｆ（ｘ）］关系用线性模式ｆ（ｘ）＝ａｘ＋ ｂ 表示，则新的防治指标（ｘ）求解模型为ｘ＝（ Ｃ·ＦＮ·Ｅ·Ｐ）×１ａ ，而传统的防治指标（ｘ′） 求解模型为ｘ′＝ （ Ｃ·ＦＮ·Ｅ·Ｐ－ ｂ） ×１ａ 。从推导过程和计算结果对两种求解模型进行了比较，结果表明，新的防治指标求解模型更具合理性。

A New Model of Calculating the Economic Threshold of Plant Disease and Insect Pest

On the basis of economic threshold model that retrieved loss equals control cost and equation that retrieved yield loss rate equals the contrast yield loss rate minus the yield loss rate of control, a new model of calculating the economic threshold of plant disease and insect pest was put forward in this paper. When the relationship between pest number (x) and yield loss rate f(x)] was f(x)=ax+b, the traditional economic threshold calculating model was x′=(C·FN·E·P-b)×1a, the new model could be expressed by x=(C·FN·E·P)×1a. Analysis and comparison showed that the new model was more rational.