What are the diseases of kidney bean and how to prevent and control them

What should we do when we encounter various diseases when cultivating kidney beans? Today I will tell you about the prevention and control methods:

See Sclerotium rot

Symptoms: The base of the stem is dark brown, with dense white filamentous hyphae bundles on the surface. Later, dark brown round sclerotia are formed on the hyphae layer.

Disease pattern and prevention and control methods: refer to melon white disease

Sclerotinia sclerotiorum

Distribution and host plants: Distributed everywhere. In addition to harming beans, it also infects other vegetables.

Symptoms: The base of the stem or vine near the ground is initially waterlogged and then turns grayish white. In a humid environment, the stem is densely covered with white cotton-like mycelium and produces black sclerotia.

Disease pattern: The sclerotia overwinter in the soil. The ascospores are first infected with the air flow. During the growth period of the vegetable plant, the mycelium is mainly in contact with each other for secondary infection. The temperature is around 20℃ and the relative humidity is above 85%, which is conducive to the occurrence of the virus.

Prevention and control methods: (1) Crop rotation. (2) Strengthen field management and apply fertilizer and irrigation properly. (3) Spray pesticides in time. The pesticides include 500 times dilution of 50% thiophanate wettable powder or 1000 times dilution of 52% carbendazim wettable powder. Spray once every 7-10 days, for a total of 2-3 times.

Bacterial blight of beans

Distribution and host plants: It occurs in the northeastern provinces, Henan, Hubei, Hunan, Jiangsu, Zhejiang and other provinces. It harms kidney beans, mung beans, adzuki beans, cowpeas and lentils.

Symptoms: Dark green water-soaked spots initially appear on the leaves, which become irregular and brown after enlargement. The diseased tissue becomes thinner and translucent, with a yellow halo around it. Old spots are prone to rupture. Young leaves are deformed when affected, and in severe cases, the diseased leaves shrink and fall off. The symptoms of stems and pods are similar to those of leaves, initially appearing as water-soaked spots, which expand into stripes (on stems) and round or irregular spots (on pods), respectively. The diseased part is sunken and reddish brown. There is often light yellow pus on the spot surface, and the surface of the infected part of the diseased pods and seeds is yellow spotting or only slightly yellow spots appear at the navel.

Disease pattern: The pathogen overwinters in the seeds and on the ground with diseased residues. After the infected seeds germinate, the cotyledons will become diseased and pathogenic bacteria will be produced in the cotyledons. They will be spread to the bean plants through wind, rain, insects, humans and animals, and invade through the stomata. High temperature and high humidity are suitable for the spread of this disease, but the disease will gradually stop at 36℃. The incubation period at high temperature is generally 2-3 days.

Prevention and control methods: (1) Use disease-free seeds for sowing. (2) Rotate crops with non-leguminous crops for two years. (3) Spray 0.5% Bordeaux mixture once every 7-10 days for a total of 2-3 times.

Bean mosaic virus

Distribution and host plants: Distributed everywhere. There are three viruses that cause bean mosaic disease: Common bean mosaic virus harms not only beans, but also some bean plants, broad beans, cowpeas and lentils. Yellow bean mosaic virus has host plants for common bean mosaic virus, including peas, soybeans, two types of clovers, white fan lentils, white sweet clover, black purple alfalfa, Tang Jing Pu, etc. The bean strain of cucumber mosaic virus only harms beans.

Symptoms: Young leaves initially have clear veins, lack green or are wrinkled and hard. Newly grown young leaves are mosaic, with the green parts protruding or concave in a bag-like shape. Some varieties become deformed after infection. Diseased plants are stunted or normal, and the fruit pods are generally normal. The symptoms caused by bean yellow mosaic virus are more serious than those caused by other strains. The mosaic color is yellower and the leaves are more seriously bent downward.

Disease pattern: The primary infection source is mainly the overwintering host plant. In addition to bean yellow mosaic virus, the infected seeds of the other two viruses are also the main primary infection sources. During the growth period, it is mainly transmitted by aphids. It takes about 1-5 minutes for aphids to absorb the virus on the diseased plants and transmit the virus on the healthy plants, but the shortest time for bean yellow mosaic is 15 seconds and 15-30 seconds respectively. At high temperature (26℃), it is mostly severe mosaic, dwarfing and curling leaves; at about 18℃, it is light mosaic; above 28℃ and below 18℃, the symptoms are suppressed; strong light and extended light time tend to aggravate the symptoms.

Prevention and control methods: (1) Breed disease-resistant varieties. (2) Save disease-free plants for seed. (3) Prevent and control aphids in a timely manner.