Witches'-Broom is caused by an unusual fungus, Pucciniastrum goeppertianum . It is included here because the symptoms are more like those of a virus than a fungal disease. It occurs in North America, Europe, Siberia, and Japan. This fungus spends part of its life on highbush and lowbush blueberry. Both of these hosts must be present for the disease to occur.
Many brooms can appear on one plant.
Young growth of the brooms is yellow or reddish, but becomes brown and shiny, then dull, and eventually dry and cracked. The plants produce no fruit on these brooms. Do not plant within 1200 feet of fir trees. Eradicate diseased plants with a recommended herbicide to eliminate the disease from a field. Pruning off the brooms will not control this disease, as it is in the entire plant.