What causes black heart in radishes? A detailed explanation of the latest prevention and control methods
Radish is a vegetable we commonly eat, rich in vitamins and various trace elements the human body needs, with excellent health-preserving and health-care effects, but some farmers have found that their radishes show black heart symptoms, and the radishes completely lose their commercial value, bringing huge losses. So what causes black heart in radishes? How should it be prevented and controlled? Let's find out together.
1. Black heart caused by oxygen deficiency
Black heart caused by oxygen deficiency in the roots: after cutting the root open, you will find that the xylem of the fleshy root has turned black, with many small black spots appearing, making it inedible. This is caused by applying large amounts of undecomposed or poorly decomposed organic fertilizer in the field, especially barnyard manure, which leads to vigorous microbial activity in the soil, excessive oxygen consumption, and suffocation of the roots, with some tissues developing black heart or black skin due to oxygen deficiency.
Prevention and control methods: The plot for planting radishes should be deeply plowed and leveled, keeping the soil loose and increasing permeability. When applying organic fertilizer or farmyard manure, it must be fully decomposed. Irrigate reasonably, strengthen intertillage, supply sufficient oxygen to the roots, and promote healthy growth. Drain promptly after rain to avoid waterlogging causing black heart or black skin. When storing radishes, the amount should be moderate and must not exceed half of the cellar capacity. Strengthen ventilation and air exchange, and control the relatively low temperature and humidity inside the cellar.
2. Black heart caused by boron deficiency
Boron is one of the indispensable elements for radish growth. Boron deficiency very easily leads to black heart, hollow heart, and rotten heart. The causes of boron deficiency are: first, a lack of boron in the soil; second, excessive application of a certain element, which inhibits the root system's absorption of boron; third, high temperature and drought conditions can also affect the root system's absorption of boron, thus causing boron deficiency.
Prevention and control methods: When applying base fertilizer, add 300-400 grams of borax, mix it thoroughly with other fertilizer granules and apply it in bands, or take the measure of spraying boron as a foliar fertilizer during the growing period. Generally, from the time radishes have 2-3 true leaves until before harvest, spray once every 10 days with a 0.2% boric acid or 0.3% borax aqueous solution, for a total of three sprays. In addition, keep the field moist to promote the root system's absorption of boron, prevent drought, and irrigate promptly during the growing period.
3. Black heart caused by black rot
Black rot is a disease caused by bacteria, mainly harming roots and leaves. When it occurs at the seedling stage, the cotyledons become water-soaked, and the root pith turns black and rots. When the leaves are affected, the entire leaf gradually turns yellow and dries up, and the pathogen also spreads along the leaf veins toward the stem and root, causing all the plant's leaves to turn yellow and die. After the fleshy root is infected, cutting the radish crosswise reveals that the vascular bundles are arranged in a radial pattern and are dark brown; in severe cases, they become shrunken and hollow, and bacterial ooze overflows from the vascular bundles.
Prevention and control methods: Avoid continuous cropping with cruciferous vegetables. When planting, choose varieties with strong disease resistance, and use 50% thiram wettable powder (at 0.4% of seed weight) to dress the seeds before sowing. Control pests such as striped flea beetles and aphids early. In the early stage of the disease, spray with pesticides such as Jiaruinong, copper-ammonia complex aqueous solution, and agricultural streptomycin sulfate for propagation, spraying once every 7-10 days for 2-3 consecutive times.
The above is an introduction to the causes of black heart in radishes and the prevention and control methods. We hope it can help you. If you want to learn more related knowledge, please stay tuned to us.