How to prevent and control hyacinth bean red spot disease? These key points must be mastered

The hyacinth bean is an annual herbaceous plant, also known as fire sickle hyacinth bean, vine bean, hedge bean, magpie bean, cha bean, moon vegetable, in the class Dicotyledoneae. There are also many varieties, such as: white hyacinth bean, purple hyacinth bean, oil bean, snake bean, pig ear bean (shaped like a pig's ear). Stems are trailing, leaflets lanceolate, flowers white or purple, pods oblong, flat, slightly curved. Seeds white or purple-black. It prefers warmth and moisture and tolerates heat. Generally sown in spring and harvested in autumn. The tender pods are an ordinary vegetable, and the seeds can be used as medicine.

The hyacinth bean, an annual herbaceous legume, has trailing stems, lanceolate leaflets, white or purple flowers, and oblong, flat, slightly curved pods. The tender pods are an ordinary vegetable. According to the color of the flowers it is divided into two types, red-flowered and white-flowered; the pod color includes green-white, light green, pink, and purple-red. Those that are smooth and glossy, hard in texture, with a thin and brittle seed coat, a beany smell when chewed, and plump grains are considered best. For medicinal use, mainly the white hyacinth bean is used. The hyacinth bean contains saponins and hemagglutinins that can cause food poisoning, so it must be cooked thoroughly when cooking. 

The hyacinth bean is quite rich in nutrients, including protein, fat, carbohydrates, calcium, phosphorus, iron, potassium, and dietary fiber, provitamin A, vitamin B1, vitamin B2, vitamin C, cyanogenic glycosides, tyrosinase, etc. The B vitamins are especially abundant in the seed coat of the hyacinth bean. In addition, there are phospholipids, sucrose, and glucose.

The hyacinth bean is sweet in taste and neutral in nature, entering the stomach meridian; its qi is fragrant without being pungent, its nature is mild and its color slightly yellow, making it most compatible with the spleen. It has the effects of strengthening the spleen, harmonizing the middle, supplementing qi, transforming dampness, and relieving summer heat. It mainly treats spleen deficiency with dampness, poor appetite and loose stools, damp turbidity pouring downward, excessive leukorrhea in women, summer dampness damaging the middle, and vomiting, diarrhea, and cramps, among other conditions.

Key points for the prevention and control of hyacinth bean red spot disease

Symptoms of hyacinth bean red spot disease It mainly damages leaves, and when the disease is severe it can also damage pods. When leaves are affected, the spots are circular, nearly circular, or irregular, 4-8 mm in size, red to reddish-brown, with darker edges. When humidity is high, a dense gray mold layer grows on the underside of the spots. When pods are affected, the spots are larger, irregular, reddish-brown, with a brown center, and later a dense gray-black mold layer. When the disease is severe, the leaves are covered with spots, causing the leaves to wither early.

Occurrence pattern of hyacinth bean red spot disease

The pathogen mainly overwinters in the soil as mycelium with diseased residues, and can also overwinter as mycelium inside seeds or as conidia attached to the seed surface. Sowing infected seeds can cause seedlings to develop the disease. The overwintering pathogen produces conidia the following spring, which infect and cause disease. After onset, the diseased parts produce new conidia, which spread through wind and rain, and can also be spread by agricultural operations. The conidia germinate and produce germ tubes, which invade through stomata or directly penetrate the epidermis, causing re-infection. During the growing season, after multiple re-infections by conidia, the pathogen accumulates in large amounts, and once suitable conditions occur, it will cause severe disease outbreaks. The pathogen prefers high temperature and high humidity; a temperature of 25-28°C and relative humidity above 85% favor disease occurrence and development. Rainy weather favors rapid spread of the disease, especially continuous rainy days or sudden clearing after rain, when the disease is severe.

Key points for the prevention and control of hyacinth bean red spot disease

① Agricultural measures: Use seeds retained from disease-free plants. In severely diseased fields, carry out a 2-3 year rotation with non-legume crops. Planting density should be appropriate, avoiding overly dense planting to facilitate ventilation and light penetration. Strengthen management and drain promptly after rain. Remove diseased leaves promptly when first seen, and bury them deeply or burn them. After harvest, thoroughly remove diseased residues and deep plow.

② Seed disinfection: Generally, seeds should be disinfected. You can soak the seeds in 45°C warm water for 10 minutes, or dress the seeds with 0.3% of seed weight of 50% thiram wettable powder.

③ Chemical control: In the early stage of the disease, you can use 50% carbendazim wettable powder at 500 times dilution, or 50% thiophanate-methyl wettable powder at 500 times dilution, 65% zineb wettable powder at 500 times dilution. Or 70% mancozeb wettable powder at 500 times dilution, or 80% Daconil wettable powder at 800 times dilution, or 75% chlorothalonil wettable powder at 600 times dilution, or 77% Kocide wettable micropowder at 600 times dilution, or 50% iprodione wettable powder at 1000-1500 times dilution and other agents for spraying, about once every 7 days, for 2-3 consecutive treatments.