When your rose plants affected by pests that gave rise to the black spots on the leaves, you can simply trim parts that are exposed to it in order not to spread to another. To prevent pests, you can use insecticides and pesticides.
In addition to the use of pesticides, you can also use a liquid made from a solution of 3 tablespoons of baking soda with water segalon. Things to note on first spraying is, on a smaller scale first, the longer the new can be raised that the overdose.
This prevents the roses are not "surprised" by zak chemistry. Wear gloves when spraying and avoid spraying when wind blows.
When some things last done routinely and properly, then the rose you will fast and flowering trees are kept healthy and far from plant pests. If you already know how to care for roses in order for fast flowering, surely you need not hesitate to plant this beautiful flowers at home.
That's all I can share at this time. If you have questions, please write below. All this and thanks