Crown Gall

Crown gall is an important disease of wine grapes when they are grown in cold climates. Most grape cultivars are susceptible to crown gall.

Major outbreaks are generally restricted to the varieties that are most susceptible to winter injury. The amount of crown gall present from year to year appears to be related to the severity of the preceding winter and the maturity of the vines.

Symptoms

Gall formation on the aerial part of the vines is the most common symptom associated with this disease. The bacterium which causes crown gall may be present in plants that do not show any symptoms.

Galls are usually noticed as swellings near the base of the vine and up the trunk. Galls on roots of grape are not typical, however the bacteria can induce a localized necrosis of roots. Young galls are soft, creamy to greenish in colour, with no bark or covering. As they age, the tissue darkens to brown. The surface becomes open, and the texture becomes moderately hard and very rough. The surface tissue of the galls turns black as it dies, but the bacterium remains alive in the vine.

Spread

A major source of diseased vines appears to be through propagation of diseased wood. The bacterium remains inside the vine until there is an injury to the trunk and, only then, invades the outer part of the trunk where it causes rapid cell multiplication and distortion of tissue-producing galls.

Management

Control of crown gall can at best be referred to as an attempt to manage this disease as there is little that can be done to control this disease once it is established in the vineyard.

Before planting or selecting vineyard sites

Select sites with good air and water drainage.
Avoid planting in frost-prone areas.
Select rootstocks that are resistant to crown gall as they can reduce the amount of crown gall that appears on susceptible scions. Certain rootstocks such as Courderc 3309, 101-14 Mgt, and Riparia Gloire are resistant, whereas Teleki 5C and 110 Richter are susceptible. See the Rootstocks page in the Vineyard Establishment section for more details.
Select hardy varieties where possible.
Prepare sites with nutrients and lime before planting to avoid vine stress due to poor nutrition or low pH.
Consider pest control programs for nematodes and phylloxera before planting through the use of soil fumigation or rootstocks. Feeding damage by these pests provides sites for the entry of crown gall bacteria.
Plant old vineyard areas where crown gall was present only after grapevines have been removed for at least two years. This is important because crown gall bacteria can survive in the remnants of the old grape plants until the debris decomposes. Success in reducing crown gall from the soil by leaving soil fallow or rotating to other crops may vary depending on the amount of vine debris that is left in the soil and how fast it breaks down.
Do not propagate wood taken from galled vines.
Specify that plant material you purchase be propagated from crown gall free plants. Producers must promote the production of certified indexed crown gall free vines.

After planting