福建连城甘薯块根苦变病因的探讨

福建连城甘薯薯块上发生的变色、变苦的病害，经病原分离，分离到了黑斑病菌，但用防治黑斑病的方法防治时，不能完全控制此病．经对土壤进行测定，发现土壤有效Ｂ的质量分数极低．用石英砂作甘薯缺Ｂ盆栽试验，得到了与连城病薯相似的症状．在用Ｂ肥和Ｂ肥加多菌灵进行防治时，能控制此病．因此我们认为连城薯病有２种病因：一为土壤缺Ｂ；二为甘薯黑斑病．

Causes of black-rot and bitter-root of sweetpotato in Liancheng,Fujian

The cross section of infected roots of sweetpotato observed in Liancheng, Fujian, was black brown and tasted bitter, and the disease was not completely inhibited by controlling Ceratocystis fimbriata isolated from roots. Analysis of the soil samples demonstrated that the mass fraction of available boron was extremely low, meanwhile, using quartz sand without boron to culture sweetpotato, the similar symptom could be found, and applying boron alone and boron with Bavistin could control the disease. It was suggested that the disease was caused by both boron deficiency in soil and Ceratocystis fimbriata .