See gourd white silk disease
Symptoms: the stem base is dark brown, with dense white filamentous hyphae on the surface, and dark brown round sclerotia is formed on the hyphae in the later stage.
Occurrence regularity and control methods: refer to Bai Juan's disease in melons.
Sclerotinia leguminosa
Distribution and host plants: distributed everywhere. In addition to harming kidney beans, it will also infect other vegetables.
Symptoms: near the ground, the base of the stem or vine is soaked in water at first, and then it is gray. In humid environment, diseased stems densely produce white cotton-wool mycelium and black sclerotia.
Pathogenesis: Sclerotinia sclerotiorum overwinters in soil. The sunlight of the ascospores first fills the airflow. During the growth of vegetable plants, the secondary infection is mainly due to the mutual contact of hyphae. The temperature is about 20℃ and the relative humidity is above 85%, which is beneficial to the occurrence of virus.
Control mode: (1) rotation. (2) Strengthening field management and rational fertilization and irrigation. (
Bacterial blight of kidney bean
Distribution and host plants: in Northeast China, Henan, Hubei, Hunan, Jiangsu, Zhejiang and other provinces. It harms kidney beans, mung beans, adzuki beans, cowpeas and lentils.
Symptoms: The primary dark green water spots on the leaves are irregular, brown after swelling, and the diseased tissue is thin and translucent with yellow halo around it. Old lesions are easy to rupture. Young leaves are deformed, and in severe cases, diseased leaves shrink and fall off. The symptoms of stems and pods are similar to those of leaves. At first, they were water-soaked spots. After expansion, they are striped spots (on the stem) and round or plastic spots (on the pod). The affected part is sunken and reddish brown. Pale yellow pus often overflows on the spot surface, and the surface of infected parts of diseased pod seeds is yellow spots or only the navel is slightly yellow spots.
Pathogenic law: germs overwinter in seeds and stay on the ground with sick and disabled people. After the seeds with buds germinate, their cotyledons become ill one after another, and pathogenic bacteria are produced in the cotyledons, which spread to legumes through wind and rain, insects, people and animals and invade from stomata. High temperature and high humidity are suitable for the epidemic of the disease, but the disease gradually stops at 36℃. The incubation period at high temperature is generally 2-3 days.
Control method: (1) Select disease-free seeds for sowing. (2) Rotation with non-leguminous crops for two years. (3) Spray 0.5% Bordeaux once every 7- 10 day, ***2-3 times.
Kidney bean mosaic virus
Distribution and host plants: distributed everywhere. There are three kinds of viruses that cause mosaic disease of kidney beans: common mosaic virus of kidney beans not only harms kidney beans, but also harms some plants such as kidney beans, broad beans, cowpeas and lentils. Kidney bean yellow mosaic virus includes not only the host plants of kidney bean common mosaic virus, but also peas, soybeans, two kinds of clover, white lentils, sweet clover, black alfalfa, Tang and so on. Cucumber mosaic virus kidney bean strain only harms kidney bean.
Symptoms: Young leaves appear bright veins, lack of green or wrinkled hard at first, but the newly grown young leaves are flower-leaf-shaped, and the green parts are bag-shaped convex or concave, and some varieties are deformed after the disease. The diseased plants are short or normal, and the pods are generally normal. The symptoms caused by kidney bean yellow mosaic virus are more serious than other strains, with yellow leaves and more serious downward bending of leaves.
Pathogenesis: The main source of primary infection is overwintering host plants. In addition to bean yellow mosaic virus, the infected seeds of the other two viruses are also the main sources of initial infection. The growth period is mainly spread by aphids. It takes about 1-5 minutes for aphids to take drugs on diseased plants and spread indoor viruses on healthy plants, while the shortest time for bean yellow mosaic disease is 15 seconds and 15-30 seconds respectively. At high temperature (26℃), most of them are heavy mosaic, dwarfing and leaf rolling; Optical mosaic around 65438 08℃; Symptoms above 28℃ and below 18℃ were inhibited; Strong light and prolonged illumination are easy to aggravate symptoms.
Control method: (1) Breeding disease-resistant varieties. (2) The diseased plants shall not be retained. (3) timely control aphids.