为了克服防治工作中的盲目性及滥用化学农药所造成的不良后果,在预测预报的基础上,本文对榆紫金花虫的防治指标进行了研究。一、白榆人工林每木叶积量 1985年至1987年,每年7月下旬在明水林场通达营林区的白榆人工林内,按径级分组,共选出130多株标准木进行了摘全叶称重。通过对各项调查因子进行加权平均得出 In order to overcome the blindness in the prevention and control work and the adverse consequences caused by the abuse of chemical pesticides, this paper studied the prevention and control index of Ulmus giganteus on the basis of forecasting and forecasting. First, Ulmus pumila per plant plot 1985 to 1987, the end of July every year in Mingshui Forest Tongdaying forest elm plantation, according to the size of the sub-group, a total of more than 130 standard trees were selected Abstract Leaf weighing. Through the investigation of the factors weighted average derived