Crown gall (Agrobacterium tumefaciens)

Symptoms

• The disease is characterized by large lumps at the base of the plant stem or on roots.
• Galls may appear higher on stems as the disease progresses.
• Galls are soft compared to surrounding plant tissues.
• If the disease affects the plant while it is young the plant may be affected to the degree where it will not produce blooms.
• All affected plants wilt readily and grow poorly.

Management

• Avoid injury to the plants.
• Purchase disease-free stock plants from a reputable supplier.
• Rogue out diseased plants early.
• Cultural control through prevention of introduction/elimination is the best method
• Chemical control of the disease is not available.
• Biological control of the disease with A. radiobacter strain K84 or K1026 reported successful.