兰花的叶片患了黑斑病,严重时需要剪除病叶,这会降低兰化的观赏价值和经济价值。我在多年养兰的实践中,为保全叶片,曾采用龙胆紫(俗称紫药水)或高锰酸钾饱和溶液防治。其方法是:任取一种药液,涂擦叶片的黑斑处,面积比黑斑略大。涂擦一次,斑块即不再扩展。这种方法比喷洒其它药液 Orchid leaves suffering from black spot disease, severe need to cut off diseased leaves, which will reduce the ornamental value of blue and economic value. I practice many years in the blue, in order to preserve the leaves, had used gentian violet (commonly known as gentian violet) or saturated solution of potassium permanganate prevention and treatment. The method is: Any way to take a solution, rub the leaves at the black spots, the area slightly larger than the black spot. Rub once, plaque no longer expands. This method than spraying other liquid