Question
Knockout rose disease
The leaves of my 3 KnockOut rose bushes have some kind of disease. It starts with a whitish spot, then the chlorophyl in the leaf disappears leaving a translucent tissue-like area in the shape of the spot, then a hole in the leaf appears. I planted these about 2 weeks ago--my second set of 3 because the first ones disintegrated quickly though I don't think it was due to the same thing. I'm sending photos. What could be causing this and how do I stop it before the damage gets more extensive? I haven't noticed any pests.
AnswerYour roses have what is called Shot Hole Fungus. It is a mildew and is caused by climatic conditions being right, such as warm days and colder nights. There are sprays in the garden centers for mildew and all will solve the problem for you. You could also try 1 tablespoon of baking soda to 2 quarts of water and spray the leaves daily until the mildew has gone.
