Root cancer of cherry blossoms

Cherry blossoms are distributed in Liaoning, Hebei, Anhui, Jiangxi, Zhejiang, Jiangsu and Guizhou in China, and mostly in Japan and Korea. Xiguang, like deep, fertile and well-drained soil, have weak resistance to smoke, harmful gases and sea tide wind. It has certain cold tolerance, shallow root system and easy cultivation. Cherry blossoms blossom in spring and are very beautiful. It should be planted on hillsides, courtyards, in front of buildings and by the side of the garden road.

The disease is a common and serious disease of cherry blossoms, which generally occurs in the areas where cherry blossoms are introduced. Serious occurrence occurred in Zhengzhou, Chengdu, Hangzhou, Jinan and Wuhan. In addition to cherry blossoms, plum, plum, peach, clove, poplar, willow, dahlia and other garden plants are also affected. The infected plants developed poorly and the leaf color was abnormal, which affected the ornamental.

Symptoms: the disease mainly occurred in the root neck and lateral roots of the plant, mostly in the grafting wound, and sometimes at the base of the trunk. Tumors of different sizes are usually produced in the susceptible site. The tumor is spherical, rough and uneven. Initially grayish white or fleshy, gradually turning brown or dark brown, and cracked. After the root system is susceptible to the disease, the development is poor, and the whisker root is very few. The growth of the aboveground part of the susceptible plant is slow, the tree potential is weak, the flowering is few, the flowering period is short, when the leaves are yellowed, early fall, and even the whole plant withered.

The pathogen is Agrobacteriurntumtumefaciens (SmithetTowns.) Conn, which is bacteria. The optimum temperature for the development of bacteria was 22 ℃.

Incidence regularity: the pathogen survived and overwintered on the tumor surface and soil of the susceptible host. It can survive in the soil for a few months to a year or so. Germs are mainly spread by Rain Water and irrigation water, and can also be transmitted by tools or pests under them. The long-distance transmission of the disease depends on the allocation of seedlings and plants. Pathogens invade the host through a variety of wounds and stimulate cell division to produce a large number of meristems, thus forming tumors. From the invasion of bacteria to the appearance of symptoms, at least a few weeks, more than 1 year. The disease is serious when the soil is moist, stagnant water and rich in organic matter. Alkaline soil is beneficial to the occurrence of diseases.

Prevention and treatment: when planting ①, healthy plants should be strictly selected, and diseased plants should not be used. ② found the diseased plant and destroyed it immediately. After digging out the diseased root, the surrounding soil was disinfected with sulfur powder mixed into the soil, with a dosage of 50-100g/ square meters. For suspicious seedlings, soak 5min with 1% copper sulfate before planting, rinse with water, and then plant. The ③ nursery should be located in areas free of root cancer, such as rotation for more than 2 years in the disease area.