What diseases are prone to occur in autumn radishes, and how should they be prevented and controlled?
Radish is the most common vegetable in China. Whether served on people's dining tables or fed to pigs as feed, it is very popular, and radish is grown over a very wide range in China. However, whether grown on a large scale or for a family's own self-sufficiency, some problems will be found. One of these is disease, and among diseases, those in autumn are the most serious. So what diseases are autumn radishes prone to? How should they be prevented and controlled? Let's take a look below!
1. Downy mildew
Symptoms: Downy mildew mainly harms radish leaves, and at the early stage of onset it begins to invade from the outer leaves. Green to yellow spots gradually appear on the leaf surface, then gradually spread and expand and turn yellow-brown; the leaves are not damaged, and along the veins they then become polygonal. When humid, white moldy material appears on the leaf surface, and in severe cases it directly causes death. Downy mildew is most likely to occur when the average temperature is 16°C, and insufficient sunlight, continuous rainy weather, excessive openness, and overly dense planting are all favorable conditions for onset.
Prevention and control method: When suspected diseased plants are found, response measures should be taken promptly and spraying should be carried out for prevention and control. If the weather is relatively dry after spraying, there is no need to spray again. If rainy and foggy weather occurs, spray once or twice more about one week apart. An available pesticide is fosetyl-aluminum wettable powder.
2. Soft rot
Soft rot mainly harms the roots, stems, and leaves of radish. When the root is infected, onset generally begins at the root tip, and at the early stage brown water-soaked soft rot patches appear. It gradually spreads upward, and in the later stage causes the heart to soften, rot, and turn into a mass, accompanied by a foul odor. When the stems and leaves are infected, water-soaked soft rot also begins to appear, and after encountering drought it stops spreading; new leaves appear at the root head, there is a clear boundary between the diseased part and the normal part, and brown juice often seeps out, causing the entire radish to turn brown and soft-rot.
Prevention and control method: When diseased plants are found, dig them out promptly, then scatter some lime into the holes of the diseased plants for disinfection. At the early stage, pesticides such as kasugamycin can be sprayed for prevention and control. Spray about once a week for one week.
3. Black rot
Symptoms: Black rot mainly harms the roots and leaves of radish. When the leaves are infected, "v"-shaped lesion patches generally appear at the leaf margins, the veins also gradually turn black, the leaf margins begin to turn yellow, and then gradually spread to the entire leaf. When the root is infected, it causes the vascular bundles to turn black, the internal tissues lack nutrients, and dry rot slowly develops, but the external symptoms are not very obvious. Poor drainage, rainy weather, insufficiently decomposed farmyard manure, continuous cropping, and other reasons can all lead to the onset of black rot.
Prevention and control method: When diseased plants are found, pull them out promptly, burn or deeply bury them, and keep them away from the original site to prevent infection, then scatter lime into the holes of the diseased plants for disinfection. During field management of radish, try to avoid injuring the radish and reduce wounds on the radish. At the early stage of onset, Haolike suspension concentrate can be sprayed for prevention and control.
The above are the diseases to which radish is relatively prone in autumn. Everyone must pay special attention when managing radish to the disinfection of the garden plot and the handling of diseased plants. Reduce sources of disease and lower the incidence rate. If not handled in time, radish cannot overwinter, and may not even last until early winter before dying in large areas. Therefore, I hope everyone can pay attention to radish pests and diseases and improve their own economic benefits.