What are the control methods for cherry blossom crown gall disease?
Cherry blossom crown gall disease is also known as crown gall. The crown gall pathogen has a very wide host range, with about 330-plus species in 142 genera across 59 families. It harms more than 600 species of plants, mainly forest plants, economic forest plants and landscape plants. Peach, plum, pear, apple, Chinese rose and cherry blossom are all highly susceptible to crown gall. Flowers and trees infected with this disease have their root development affected, often causing nutrient deficiency, showing a weakened state, and finally dying.
Symptoms: It mainly occurs at the root crown and on large roots, and sometimes also on lateral roots. The main symptom is the formation of tumors of varying sizes and irregular shapes on the roots. In the early stage of the disease, they are white with a smooth surface, gradually turning dark brown with an uneven surface, resembling a cauliflower. After cherry trees are infected with this disease, in mild cases they grow slowly, the tree vigor weakens, and fruiting capacity declines; in severe cases the entire plant dies.
Control methods:
1. When introducing nursery stock, eliminate diseased seedlings and select disease-free nursery stock.
2. Disinfection of nursery stock. Before transplanting nursery stock, soak the roots in a 1% copper sulfate solution for 5 minutes, then transfer them to a 2% limewater solution and soak for 1 minute to prevent bacteria carried by the nursery stock and soil. If diseased plants are found, promptly cut off the root tumors with a small knife, treat the wounds with a 1% mercuric chloride solution or antibacterial agent 402, and apply Bordeaux paste for protection. The cut-off root tumors should be collected and burned.
3. Treat the soil and use chemicals to control the disease tumors. When planting, mix ferrous sulfate with the soil to change the soil acidity. When plants develop the disease, promptly cut off the root tumors with a small knife, treat the wounds with a 1% mercuric chloride solution or antibacterial agent 402, and apply Bordeaux paste for protection. The cut-off root tumors should be collected and burned. At the same time, irrigate the plant roots with antibacterial agent 402 for soil disinfection. For diseased plants more than three years old, you can try treating the disease tumors with bacteriocin (a hydrocarbon containing xylenol and cresol); bacteriocin has a very good control effect on nursery stock root tumors. However, because cherry trees are sensitive to many chemicals, it is recommended to conduct a small-scale trial first, and only use it on a large scale after the trial is successful.