Witches' Broom
|
|
A Witches broom (or Witch broom) is a minor deformity in a plant or tree where the natural structure of the plant is changed. A dense mass of shoots grow from a single point, with the resulting structure resembling a broom or a bird's nest. One example of this would be cytokinin, a phytohormone, interfering with an auxin-regulated bud. Usually auxin would keep the secondary, tertiary, and so on apexes from growing too much, but cytokinin releases them from this control, and that is why these other apexes grow into witch brooms. A witches broom growth may last several years and can be caused by many different types of organisms, e.g. fungi, mites, viruses, fungi, mistletoe, insects, and nematodes.