MY KNOCKOUT ROSES HAVE THAT AWFUL INSECT????THAT MAKES RED GROWTH AND LARGE THORNS AND] NOT PRETTY ROSES. I AM SO AFRAID OF LOSING THEM AS I HAVE SEVERAL. THEY GET LOTS OF SUN.
Knockout Rose Diseases
First things first. It is not an insect but rather a Virus called Rose Rosette that infects some roses causing mottled and mutilated redish growth. The virus/disease is believed to be spread by tiny mites. Spraying the rosebushes with a miticide such as Avid or Floramite will help keep them safe. The new growth on rosebushes, including Knock Outs can be different looking and be a rich deep red or maroon color, it is actually very pretty and nothing to worry about. The infected growth has a mutilated look to it, twisted and looking similar to an old broom which is why it is also sometimes called Witches Broom. The sad and heartbreaking thing about rose rosette is, once infected, there is no cure for it. The rose is doomed and will die, this cane take a long period of time or can be rather quickly. My advice is that if you Know For Sure that the rosebush has rose rosette, you are doing yourself and other rosebushes a favor by getting rid of those infected.