臺灣柑桔毒素病問題與生產改進

柑桔之栽培歷史雖然相當悠久，可算是最古老園藝作物之一，但柑桔毒素病研究卻是新近之事，當美國加州大學之福瑟氏（H. S. Fawcett）最先證明柑桔鱗皮病（Psorosis）為一毒素病時，距今不過三十餘年。而此方面集力加緊研究則始於四十年代初葉，南非立枯病（Tristeza）威脅整個世界柑桔事業之際。

The achievements of citrus virus studies of the world in the past decade or two have directed our attention to the importance in this field. Besides the known 'Likubing' in Taiwan, the author has, recently, proven the existence of at least three other citrus virus diseases in Taiwan, namely exocortis, psorosis and cachexia-xyloporosis. Owing to the resistence of Rangpur lime and trifoliate orange to tristeza to which 'Likubing' belong, these rootstocks have been used in Taiwan to some extent without knowing that these happen to be intolerent stocks to exocortis. Thus recommendation of using these stocks cannot be wisely made unless proper precautions are taken. Further, the transmissibility of exocortis through tools and fingers makes the existence of this disease more important. Up to the present, recognized citrus virus diseases are so numerous and indexing of all of them so tidious that the utilization of nucellar citrus lines, though require considerable time to develop, has ultimately become very practical. Sooner or later it will become an appropriate trend for us to follow if goal of citrus improvement is to be attended.