上海地区樟树黄化病的发生与防治

黄化病是樟树的一种常见病害，可严重影响城市景观和绿化效果。本研究对上海市樟树黄化病的症状、发病特点及发病原因进行了较为系统的调查，结果表明：樟树黄化病主要是由于缺铁而引起的生理性病害；病害发生的主要原因是土壤质地太差，受建筑垃圾污染严重，导致土壤碱化，影响铁离子的有效吸收；发病特点为冬春季节及幼树的黄化率较高。在此基础上提出了以土壤改良为主，药液治疗为辅的防治对策，并给出了具体的防治建议。

Investigation of the Causal Factors of Camphor Tree Yellows and Control Measure in Shanghai

The camphor tree yellow is a common disease in Shanghai and the value of these tree landscapes have been decreased seriously.The investigation of the symptom,characteristic and causal factors of the disease in Shanghai was made in this paper.The result showed that camphor tree yellow was a physiological disease.The key factors that disease occur were the soil texture because of too clay and harden;and the soil was polluted by the building garbage and sewage resulting in high soil pH value,in which Fe element was hardly absorbed by plant.The disease incidence of plant in spring and winter was higher than other seasons,and the incidence of young plant was higher than old plant.Therefore,the control measures that treat soil improvement as key measure,and chemical as secondary one were suggested.