What is Witches’ Broom of Cherry?
Witches’ broom on a cherry can be caused by many things. The prolific stunted or distorted shoots known as witches’ broom can be a symptom of fungal, bacterial, or viral infection. Witches’ broom can also be caused by insect, animal, or human damage to a tree. For example, if you accidentally nick a tree trunk with the mower or weed whacker, it may produce witches’ broom from the wound. Witches’ broom can also form in wounds caused by parasitic plants or areas where bark has been chewed or worn away by insects or animals. Though witches’ broom on a cherry can develop from any damage, it can also be caused by a fungal pathogen known as Taphrina, specifically T. cerasi or T. wiesneri. This fungal disease causes close bunches of quick growing, small branches to form on other cherry tree branches. If left alone, these new branches usually bloom and drop their leaves earlier than other branches of the tree. White spores are often visible on the undersides of any foliage produced on the branches infected by fungal witches’ broom. Cherry leaf curl may also develop on infected branches. Eventually, the growth of the short, stubby branches of witches’ brooms will disrupt the flow of sap and the host branch will die back.
Treating Witches’ Broom Cherry Symptoms
Since fungal cherry witches’ broom is generally not considered a serious disease, there have been no fungal treatments developed for it. Any type of witches’ broom will interrupt the flow of xylem and phloem in a tree’s vascular system, causing dieback. Cherry witches’ broom control is usually achieved simply by pruning away the growth of affected branches. As with any diseased plant, proper sanitation of pruning tools is important to prevent further spread of disease. After trimming away witches’ broom, disinfect tools with bleach or alcohol.
