White radish white spot disease affects the quality, how to prevent and control white radish white s

Before sowing, the seeds should be soaked in warm water at about 50 degrees Celsius for about 20 minutes, and then put them in cold water to cool before sowing. It can also be used to sterilize seeds with agents such as formabi, carbendazim, etc. At the same time, crop rotation should be implemented with cruciferous vegetables, and the sowing time should be appropriately delayed.

In the early stage of vitiligo, spray carbendazim and other agents in time to carry out prevention and control, once a week, for about 30 days. There are pale or yellowish-green halos around the periphery, but the halos around the dorsal lesions are sometimes not obvious. In the later stages, the lesions merge with each other to form large irregular lesions.

When wet, a pale gray mold develops on the back of the lesion. Later lesions become white and translucent. and ruptured perforated.

Generally, the outer lobes occur first and spread upwards. The disease is a fungal disease. The pathogen overwinters with the remains of the diseased plant on the surface, and can also overwinter on the seeds or seeds, and spreads with wind and rain in the next spring.

The relative humidity of the air at the onset of vitiligo is more than 60%. It is easy to get sick in the weather when the temperature is low, there is a lot of condensation in the field, fog and rain. In addition, factors such as continuous cropping, low-lying terrain, overwatering, and early sowing can also contribute to disease epidemics.

There are also some differences in disease resistance among different varieties <>

1. Seed treatment. Choose disease-free plants to prevent germs from carrying seeds. Infected seeds can be soaked in 50 warm soup to destroy the germs on the seeds. Choose green-skinned disease-resistant varieties, and white-skinned varieties are prone to disease. In general, hybrids are more resistant to disease <>

2. Chemical control. In the early stage of the disease, you can choose to use 800 times of 25% carbendazim wettable powder, or 800 times of 50% carbendazim sulfonate wettable powder, or 50% thiophanate-methyl wettable powder 500 times, or 50% mixed sulfur suspension 600 times, or 40% polysulfur suspension 600 times, or 65% thiobacterium mycocarb wettable powder 1000 times, or 50% multi-mocarb wettable powder 800 times and other spray control, each spray 50 liters, about 15 days apart. <>

First of all, it is necessary to choose some soil with high terrain and good drainage, and then be sure to fertilize in time, and secondly, it is necessary to spray the corresponding pesticides, so that it will have a good control effect on the white spots of white radish.

First of all, when planting, we must choose the soil is more fertile and broad land, and in the process of fertilization, we must choose farmhouse fertilizer, do not use the fertilizer bought outside, but also often water more, to prevent the occurrence of pests and diseases, if there is a situation of small insects, then we must spray insecticides in time.

Choose excellent varieties, do not choose white-skinned varieties, treat the selected seeds to a certain extent, or carry out seed dressing, and spray them in the early stage of the disease, so as not to let it spread.

Disease name]: radish black spot disease.

Symptom characteristics]: Mainly harmful leaves. The leaves are initially black-brown to black with slightly raised small round spots, the later enlarged margins are pale, the center is light brown to gray-brown lesions, 3-6 mm in diameter, and the concentric whorls are not obvious.

When the humidity is high, pale black mold grows on the lesions, that is, the conidia and conidia of pathogenic bacteria. The diseased part is brittle and easy to break. If the disease is severe, the confluence of the lesions will cause local death of the leaves.

Leaves, stems, and pods can all be diseased. The lesions on the stems and peduncles are mostly black-brown oval patches.

Pathogenesis]: Pathogenic bacteria with hyphae.

or conidia survive on diseased leaves and are the primary source of infection throughout the year. In addition, there are hyphae lurking in the germ tissue of diseased radish seeds, which invade the roots when the seeds germinate. The onset of the disease is 25 at a moderate temperature, with a maximum of 40 and a minimum of 15.

Prevention and control methods]:

1) Choose black spot resistant varieties such as Tianzheng Qiuyu No. 1 radish.

2) Large-scale crop rotation, turning over the land in time after harvest, cleaning the pastoral, and reducing the source of bacteria in the field.

3) Increase the application of fully decomposed organic fertilizer, strengthen management, and improve the disease resistance and disease resistance of radish.

4) Seed disinfection, seed dressing with 50 Fumei double wettable powder or 75 Dakonine wettable powder, or 50 iprodione wettable powder with seed weight 0 4. (5) Pharmaceutical prevention and control. The fungicides that are effective against melanoma-induced by Alternaria are:

75 chlorothalonil wettable powder 500-600 times, 50 iprodione wettable powder 1000 times, 58 methalin-manganese-zinc wettable powder 500 times, 80 mancozeb.

WP 600 times liquid. The best time to prevent and treat the disease is to start taking medication before the onset of the disease. Once every 7-10 days, 3-4 times in a row. Mancozeb can only be sprayed once per growing season to prevent manganese ions from exceeding the standard.

If there are black spots on the skin of the radish, it may be caused by the environment during storage, and it will not affect the consumption of the radish. If there are black spots on the flesh of the radish, it is recommended not to eat it. 4.

White radish should be eaten raw, but it should be noted that it should not be eaten within half an hour after eating to prevent its active ingredients from being diluted.

Black spots on white radish, if there are black spots on the epidermis, it may be caused by the environment during storage, this does not affect the use, if there are black spots on the flesh under the skin, this is not recommended.

From the ** point of view, the light soil color on the radish is not like a disease, if the skin is peeled with a knife, there are no traces inside, it should be a slight injury caused by contact with the soil during the growth and expansion of the radish, and it does not hinder eating.

At the beginning, the leaves scattered gray-white round spots, which were light gray round to nearly round after enlargement, with a diameter of 2 6 mm, and a thick green halo around the periphery of the spots. In the later stages of growth, gray mold grows on the back of the lesions.

The main symptoms of radish white spot disease are: mainly damage the leaves, the leaves are scattered gray-white round spots at the beginning of the disease, and then expand into light gray round to nearly round, with a diameter of 2 6 mm, and there is a strong green halo around the periphery of the spots, but the halo around the lesions on the back of the leaves is sometimes not obvious, and the lesions are connected into pieces when they are severe, causing the leaves to die, and the lesions are not easy to perforate, and gray mold grows on the back of the lesions in the late growth stage, that is, the mycelium of the pathogens.

Mainly damage the leaves, the leaves are scattered gray-white round spots at the beginning of the disease, and then expand into light gray round to nearly round, with a diameter of 2 6 mm, and there is a thick green halo around the peri-spot edge, but the halo around the leaf back is sometimes not obvious, and the lesions are connected into pieces when it is severe, causing the leaves to die, and the lesions are not easy to perforate, and gray mold grows on the back of the lesions in the late growth stage, that is, the mycelium of the pathogens.

Radish will grow some white spots, and it will also be particularly wilted, and the color of the radish surface is also particularly dull, etc., which are the main symptoms of radish white spot disease.

At the beginning of the disease, the leaves are scattered with gray-brown tiny round spots, and then gradually expand into irregular round lesions, ** become gray-white, with 1-2 inconspicuous wheel lines, and there are pale or pale yellow-green halos around the periphery, with a diameter of 6-18 mm. In the later stages, the lesions merge with each other to form large irregular lesions. When wet, a pale gray mold develops on the back of the lesion.

In later stages, the lesions become white and translucent, and they are ruptured and perforated. Generally, the outer lobes occur first and then spread upwards.

This is very easy to happen when the soil is too moist and too much watered, and there is no timely topdressing, no temperature control, and no control of light intensity.

The air humidity is above 60%, and the temperature is particularly low, the weather is not very good, it often rains, and there is a lot of fog, too much watering, the terrain is relatively low, and the disease resistance of the seeds is not very good.

The temperature was too high and there was too much watering, while there was no attention to management, and there was no regular fertilization, and at the same time there was no pest prevention.

<> Symptoms: Mainly damage leaves. At the beginning of the disease, the leaves are scattered gray-white round spots, which are light gray round to nearly round after enlargement, with a diameter of 2 6 mm, and there is a dark green halo around the periphery of the spots.

In the later stages of growth, gray mold grows on the back of the lesions. Pathogenesis: The disease is caused by fungi.

As long as the conditions are suitable, the pathogenic bacteria can germinate and invade from the stomata, forming a primary infection, and the pathogenic bacteria are produced on the lesions and spread by rainwater splashing, and are re-infected many times. Leukoplakia is a low-temperature disease. The suitable temperature for the onset of the disease is 11 23, and it is easy to get sick after rain.

It is flourishing in the northern vegetable area from August to October; In the middle and lower reaches of the Yangtze River and vegetable areas near lakes, it can occur in spring and autumn, especially in rainy autumn. Prevention and control methods: implement crop rotation for more than 3 years; selection of disease-resistant varieties; Pay attention to leveling the land and reducing water accumulation in the field; Sow seeds at the appropriate time and increase the application of basal fertilizer.

Pharmaceutical prevention and control: spraying in the early stage of the disease, the commonly used agent is 25% carbendazim wettable powder 400 500 times liquid; 800 times of 40% polysulfide suspension; 50% polymoldin wettable powder 800 times liquid; 65% methamphetamine wettable powder 1000 times liquid; 50% thiophanate-methyl wettable powder 500 times liquid; 50% benzyl wettable powder 1500 times liquid. The above agents are dosed at a dosage of 50 60 liters per 667 meters, and they are treated once every 15 days or so, and 2 or 3 times in a row.

The pathogen mainly uses mycelium, especially the mycelium at the base of the conidia peduncle to overwinter and summer with the diseased leaves, and can also overwinter with mycelium in the diseased part of the plant, and can also attach the conidia to the seeds for overwintering and summering. When conditions are suitable, the bacterium produces conidia that spread with wind and rain, and fall on the host to germinate and invade, causing initial infiltration. After the onset of the disease in the field, conidia were produced on the lesions and re-infected.

Diseases can occur in the temperature range of 5 28, but 11 23 is the most likely to occur, in this temperature range, the relative humidity is higher than 62%, or the rain is more than 10 mm. In autumn, when there is a lot of rain, the temperature difference between day and night is large, and the leaves are easy to condense, the disease is easy to spread. The disease generally occurs mildly in spring, and only occurs on some left-over plants.

Plants are weak in growth, poor in disease resistance and susceptible to diseases; Continuous cropping plots and early-sown plots tend to have a more severe disease. FYI.

Judging by **, it should be radish black root disease.

Prevention and control measures: 1. Implement 3 4 years of crop rotation; Reasonable dense planting, strengthen fertilizer and water management, apply fully decomposed organic fertilizer, increase potassium and phosphorus fertilizer, and enhance tree potential; Remove the diseased plants in time to reduce the source of the disease.

2. In the early stage of the disease, the following fungicides are used for prevention and control: polyantimycin; Downy mildew, or Oxazalen.