In both new and established plantings, it can be applied twice per growing season. Refer to your state's spray guide for the most current fungicide recommendations. This disease is caused by the bacterium Agrobacterium tumefaciens . Since blueberries are grown on acid soils and the crown gall bacterium does not grow well in an acid situation, the disease is uncommon. Globose, pea-size to large galls occur on low branches, twigs, and at the base of canes near the ground.
Injured tissue is more likely to contain galls.
Management Sanitation, purchasing healthy nursery plants, and maintaining proper soil conditions are the most reliable controls. A closely related bacterium, Agrobacterium radiobacter , produces an antibiotic called Agrocin and is available as a biological control agent for use either as a soil treatment or for dipping the root system of bushes prior to planting. This control measure is not recommended unless the planting has a history of crown gall problems.