Crown Gall Disease of Rose: Causes, Symptoms And Management 

Crown gall disease is an important disease of roses worldwide and can affect roses of all ages. Crown Gall Disease is caused by the bacteria Agrobacterium tumefaciens. It causes the formation of galls or tumors on the stem, roots or crown of the plant, which can lead to stunted growth and even death. In this article, we will explore the causes, symptoms, favorable conditions for disease development and management practices.  

Crown gall disease is also a threat to the nursery industry, as infected plants can serve as a source of infection for healthy plants. The development of crown gall disease of rose is influenced by the disease triangle, which includes the presence of the pathogen, susceptible host, and favorable environmental conditions. The disease is favored by warm and moist conditions and can spread rapidly under such conditions.  

Type of Infestation

The disease cycle of crown gall disease of rose includes primary infection and secondary infection with mode of survival.  

• The primary infection occurs when the bacteria enter the plant through wounds or natural openings, and the T-DNA is inserted into the plant’s genome, causing the formation of galls.  
• The secondary infection occurs when the bacteria are transferred to other plants through contaminated soil, tools or irrigation water. The bacteria can also survive in the gall tissue of infected plants, serving as a source of infection for healthy plants.  

Scientific Name: Agrobacterium tumefaciens 

Most Affected States

Crown gall disease of rose is a widespread disease in India, affecting rose plants in many states. Some of the major affected states include Uttar Pradesh, Tamil Nadu, Maharashtra, Karnataka, and Punjab.  

Symptoms of Rose Crown Gall

The symptoms of crown gall disease of rose vary depending on the severity of the infection.  

• Initially small, soft and light-colored galls appear on the stems, roots or crown of the plant. 
• As the disease progresses, the galls become larger, harder, and darker in color and they can distort the shape of the plant.  
• The infected plants may also exhibit stunted growth and reduced flower production.  

Control Measures

Crown gall disease management can be achieved through cultural practices, mechanical control, biological control and chemical control.  

Cultural Measures

Cultural practices such as crop sanitation, crop diversification and soil management are crucial in controlling crown gall disease.  

• Crop sanitation involves removing and destroying all infected plants, dead plant material and weeds in the area to prevent the spread of the disease. Farmers should also remove all plant debris and soil from pots and benches, disinfecting them before use.  
• Crop diversification involves planting non-host crops in between rose plants to reduce the disease’s spread.  
• The use of raised beds and well-drained soil can also reduce the risk of infection. 

Mechanical measures

• Destruction of infested/dead plant materials can reduce the spread of crown gall disease in rose. 
• Prune out the gall tissue. 

Biological Measures

One approach to biologically control crown gall disease is the use of soil amendments such as Agrobacterium radiobacter K84, which is a non-pathogenic strain of Agrobacterium Radiobacter that can outcompete the pathogenic strains for space and nutrients. This can be used to prevent the colonization of the pathogenic bacteria in the first place.   

Chemical Measures

Chemical control of crown gall disease can be achieved by applying certain fungicides and bactericides. Some of the commonly used chemicals are,