Studies on the Control Threshold of Braidysia olaiphage in Chinese Chive Field

The regression analysis on field investigation data of the relationship between Braidysia olaiphage larva density and the yield of Chinese chive was done and a positive correlation(r=0.816)between the larva density and the Chinese chive yield loss was found.Based on the recent year Braidysia olaiphage larva field control experiment data,the cost of the pest control and the marketing price of Chinese chive,the yield loss coefficient and the critical economic value were calculated,and the pest control index was determined in the point of view to improve the benefit of economy,ecology and sociology.In addition,a forecast mode to determine the control index was proposed based on the regression analysis of input/output ratio,larva density,control cost,price and control effect.