This plant disease is caused by soil-inhabiting bacteria (Agrobacterium tumefaciens) that infect many ornamentals, fruits, and vegetables in the garden. The bacteria are often brought to a garden initially on the roots of an infected plant, and are spread with the soil and by contaminated pruning tools. The bacteria enter the shrub through wounds in the roots or at the base of the stem (the crown). They produce a substance that stimulates rapid cell growth in the plant, causing gall formation on the roots, crown, and sometimes branches. The galls disrupt the flow of water and nutrients up the roots and stems, weakening and stunting the top of the plant. Galls do not usually cause the shrub to die.
Crown gall cannot be eliminated from the shrub. However, infected plants may survive many years. To improve the appearance of the plant, prune out and destroy affected stems below the galled area. Sterilize pruning shears after each cut with rubbing alcohol. Destroy severely infected shrubs. The bacteria will remain in the soil for 2 to 3 years. If you wish to replace the shrub soon, plant only resistant species. For a list of plants resistant to crown gall, see Trees and Shrubs Resistant to Crown Gall. For more information about crown gall, see Crown Gall.
Plant Care for Euonymus