Chinese cabbage yellow leaf disease mainly harms the foliage, how to prevent and control Chinese cab

After continuous precipitation, it is necessary to "drain" as soon as possible, and do not have water accumulation; At the beginning of the onset of the disease, it is necessary to pull out the cabbage with symptoms, and then use drugs for "spraying", it is recommended to use methyl butozine is the best; Before sowing, it is necessary to do a good job of cultivating the land, and prepare the nutrient ratio in the bottom fertilizer, and apply the bottom fertilizer. When fertilizing, you can not apply nitrogen fertilizer alone, and do a good job of drainage and irrigation in the field according to factors such as weather changes and soil conditions. Remove the diseased leaves in time and adjust the permeability of the field.

The area covered by the top film should be minimized, and the China Agricultural Network suggests increasing the area of the insect net, increasing the ventilation in the shed, and preventing the high temperature in the shed from causing the cabbage leaves to shrink and affect the quality of the cabbage. Or cover the roof of the shed with a shade net to make the cabbage grow normally. 800 times of 25% methamanine wettable powder, 800 times of 40% Fumei double wettable powder, or 600 times of 80% anti-mold treasure wettable powder, or 1000 times of 15% chlormycolin water, or 400 times of 5% bacterial toxin water agent for root irrigation, 200 ml per plant.

The focus is to grasp the prevention and control work before the seedling period and flowering and fruiting, and spray the vegetable and fruit Zhuang Tiling in the flowering and fruiting period to improve the disease resistance of vegetables. The agents often used for this kind of disease are mainly dimetallin, carbendazim, thiophanate-methyl, tebuconazole, etc., adding a new high lipid film in the agent, which can improve the efficacy, high temperature, even rainy weather, insufficient light, poor seedling resistance, and off-season cultivation plants are susceptible to disease. It can be seen from its disease conditions that it is also very important to clean up the field after this stubble of cabbage, so as to avoid pathogenic bacteria from infecting the next crop.

Trichoderm agent is a good biological fungicide, its efficacy is long-lasting, stable, and will not cause harm to humans, animals and the ecological environment. When transplanting vegetables, 2g of Trichoderma fungi agent was applied to each plant, which can grow more and longer hyphae in the soil around the roots of the plant to infect Fusarium wilt through heavy parasitism.

1. Choose disease-resistant varieties. Such as Changchun fast food, Shenyang fast food, Jiyan No. 3, single miscellaneous No. 1 rape, etc. Choose heat-resistant and disease-resistant varieties, such as 87-114, Jiaobai No. 8 and other varieties.

2. Sow seeds at the right time, generally not too early, and try to avoid the high temperature and dry season.

3. Strengthen field management. Squatting seedlings moderately, change the habit of squatting "full moon", prevent soil drought at the seedling stage, and water and cool down frequently in case of high ground temperature in dry years at the seedling stage to ensure the normal development of the root system.

4. Apply Huimanfeng active liquid fertilizer, 250-500 ml per 667 square meters, dilute 400-600 times or 400-500 times of Fengbao liquid fertilizer No. 1, and spray 2-3 times. Apply 300 times of "Kenyi" microbial active organic fertilizer.

5. Pharmaceutical prevention and control. Combined with insect control, spray or water 600-700 times of polysulfur suspension, or 50% thiophanate-methyl wettable powder 500 times, or 50% mixed sulfur suspension 500 times, or 50% benomyl wettable powder 1500 times, or 200-300 times of carbendazim concentrated solvent, 100 ml per plant. Once every 10 days or so, 1 or 2 times for prevention and treatment.

I think that Chinese cabbage yellow leaf disease is a disease that mainly harms the foliage, if we want to better prevent and control this disease, we should take corresponding measures in advance and spray the ** medicine on the surface of Chinese cabbage.

Agricultural control, the selection of heat-resistant and disease-resistant varieties, such as 87 114, Jiaobai No. 8 and other varieties; Choose a plot with a recreation period of at least 1 month and make the ground level; In case of dry weather, watering and cooling should be carried out decisively at the seedling stage to prevent root injury and eliminate the channel of pathogenic bacteria invasion.

Pesticides. Because my Chinese cabbage is sprayed with pesticides every year, and the leaves have never yellowed, I should use pesticides to control them.

It should be downy mildew of cabbage, when the leaf is diseased, the first water-soaked green spots are produced, and with the development of the disease, white downy mildew is produced on the back of the lesions, and the lesions gradually turn yellow to yellow-brown, and the expansion of the lesions is polygonal due to the restriction of leaf veins. However, it is also amorphous. Severe disease can cause the whole leaf to dry up.

The peduncle and seed pod are fat, distorted, and have pitted brown lesions, and when wet, they have white downy mildew.

Can be used with Frosturea · Manganese-zinc, downy mildew, ethylphosphine aluminum · Manganese-zinc, methae, manganese-zinc, enoylmorpholine, downy mildew · Plague net, silver farry (flumichlor. Dimycocarb), Pulik (downy mildew hydrochloride) and other foliar fertilizer sprays, sprayed continuously once every 7 days.

Ask the experts, what kind of fungicide is used? How many times in a row?

Pesticides. Because my cabbage was treated with pesticides, the yellow leaf disease was cured, so pesticides should be used to prevent and control it.

selection of disease-resistant varieties for agricultural measures; Sowing should avoid the hot and dry season; Squatting seedlings should be moderate to prevent soil drought at the seedling stage and ensure the normal development of the root system. For root irrigation, you can choose 600 700 times of 40% polysulfur suspension, or 50% thiophanate-methyl wettable powder 500 times, 50% mixed sulfur suspension 500 times, 50% benbenazim wettable powder 1500 times, and 200 300 times of synergistic carbendazim wettable powder, etc., every 10 days or so, once in a hundred days or so, even 1 2 times.

1.Potassium and magnesium deficiency in Chinese cabbage can lead to yellowing of leaves. Since these two mineral elements have strong fluidity in the plant, in the case of short supply, Chinese cabbage will transfer potassium and magnesium from old leaves to new leaves through its own regulation.

Therefore, leaf yellowing caused by potassium and magnesium insufficiency first appears on the old leaves, that is, on the leaves around the Chinese cabbage. The specific manifestations of the two elemental deficiencies are different. The leaves of potassium-deficient cabbage are yellow with gold rims, and gradually expand to the center of the leaves with the increase of nutrient deficiency. Leaf yellowing caused by magnesium deficiency mainly occurs between mesophyll veins.

The key to avoiding potassium and magnesium deficiency in Chinese cabbage is to apply sufficient basal fertilizer to ensure the continuity of nutrients**. Magnesium fertilizer is mainly supplemented with organic fertilizer and calcium, magnesium and phosphorus fertilizer, but Chinese cabbage needs potassium fertilizer, so in addition to basal fertilizer, top dressing should also be carried out at the beginning of grain filling. If elemental deficiencies are already present, foliar fertilizer spraying is a faster way to supplement.

2.There are three kinds of leaf yellowing caused by improper fertilization: one is that the applied organic fertilizer is not completely decomposed, and the ammonia and heat released in the soil will destroy the root system of Chinese cabbage, resulting in poor root development and insufficient absorption of mineral elements and water.

Obstacles can cause yellowing of leaves; Secondly, if the amount of chemical fertilizer is too large or the application is not uniform enough, and the contact with the chemical fertilizer with too large concentration, the root system will be damaged and the leaves will turn yellow; Third, the content of effective nutrients in the soil that can be absorbed by the roots of Chinese cabbage is insufficient, resulting in malnutrition of Chinese cabbage and yellowing of leaves. The amount of fertilizer is not exceeded, and spreading evenly is an important measure to avoid burning seedlings and causing yellow leaves. In order to avoid the yellowing of cabbage leaves caused by improper release, it is necessary to ensure that the applied organic fertilizer is fully fermented and decomposed; Secondly, the organic fertilizer should be evenly sprinkled, and a small amount of top dressing should be applied in batches to avoid burning the root system if it is too concentrated or too close to the root system; Third, the soil must be kept loose, breathable and with a suitable moisture content to ensure good growth of the root system and the effective use of nutrients in the soil around the root system**.

3.In natural saline-alkali soil or secondary salinized vegetable land, soil salinization caused by excessive application of chemical fertilizer and improper application of organic fertilizer will also lead to yellowing of Chinese cabbage leaves, because in the soil with too high salt content, the root system will produce salt stress, which makes it difficult for the root system to stretch and bind, weaken its absorption capacity, and make the nutrients and water required for the production and growth of Chinese cabbage unable to be effectively supplied. The high multiple cropping index of vegetable land in China, and the long-term blind application of excessive chemical fertilizer to pursue high yield, resulting in a large amount of mineral salt in the soil not being absorbed and utilized, is the main reason for the secondary salinization of the soil.

In order to avoid yellowing of Chinese cabbage due to high salt content, and to avoid saline-alkali soil when selecting a site, fertilization must be tailored to soil fertility and fertilizer requirements. When choosing organic fertilizer, the use of commercial organic fertilizer should be avoided as much as possible, and the farmhouse fertilizer that is completely decomposed should be chosen. 4.

The water content is too high, the root system of Chinese cabbage is small, and the absorption capacity is weak, but the ground leaf area is large, and the water evaporation loss ability through transpiration is strong. In order to ensure the good growth of Chinese cabbage, a high soil moisture content is required to improve the water absorption efficiency of the root system. However, when the soil moisture content.

This disease is usually caused by fungal infection, and carbendazim solution can be tried to prevent it.

The yellow leaf disease of Chinese cabbage harms the foliage, how to prevent and control the yellow leaf disease of Chinese cabbage? The first method is agricultural prevention and control, the selection of disease-resistant varieties; Sowing should avoid the hot and dry season; Squatting seedlings should be moderate to prevent soil drought at the seedling stage and ensure the normal development of the root system. The second should be the prevention and control of pesticides, irrigating roots with pesticides, you can choose 40% polysulfur suspension 600 700 times liquid, or 50% thiophanate-methyl wettable powder 500 times liquid, 50% mixed sulfur suspension 500 times liquid, 50% benmonyl wettable powder 1500 times liquid, synergistic carbendazim wettable powder 200 300 times liquid, etc., every 10 days or so for prevention and control, even prevention 1 2 times.

Pesticides. Because after my cabbage was sprayed with pesticides, the yellow leaf disease disappeared, so pesticides should be used to prevent and control it.

Melanoma.

Cabbage leaf spot is a common disease of cabbage throughout the growing season. Main symptoms: ** part from brown to gray-white, the periphery is a pale yellow halo, the periphery of the lesion on the back of the leaf is dark green, the later lesion becomes white and translucent, and finally ruptures and perforation.

The lesions are round, 2-6 mm in diameter, light brown or black-brown, with concentric rings, and often surrounded by yellow halos. There is black mold on the lesions, that is, the conidia of the fungus and its spore stalks. The petiole lesions are elongated and fusiform, with the same characteristics as the leaf lesions.

The leaves, stems, peduncles and pods of the remaining plants can also be damaged. In severe cases, the leaves are covered with diseased spots, turning yellow and dry.

There are basically three reasons for this, one is a nutritional problem, two is a temperature problem, and three is an air quality problem. However, now the weather is hot should be a little more hot, pay attention to watering, the water should not be too wet, the soil is too wet, the weather is hot, the plant is stuffy in it, and it is easy to rot the roots. Try to choose soil with good aeration.

After the harvest of vegetables or other crops in the previous season, the garden was not cleaned well, so there were more pathogens in the vegetable garden, which led to the occurrence of this disease; The density of cabbage planting is too dense, and the ventilation and light transmission are not very good, and over time the phenomenon of Verticillium wilt appears.

Sandy loam and loam soils are most suitable, and they should be close to water sources for easy irrigation. Apply 1000 1500 kg of fully decomposed manure and compost or 45 75 kg of special fertilizer for vegetables per mu, and make ridges to make furrows after land preparation, and furrows are wide and meter. After the previous greenhouse cultivation, do not dismantle the shed, leave the top film, remove the skirt film, the pathogen of cabbage blight overwinters in the soil, and the ground temperature is higher than 10 when it enters the saprophytic stage, and the pathogenic bacteria are scattered from the roots, and can also spread through rain, irrigation water, fertilizer or seed spread.

Pathogenic bacteria can infect plants under the condition of soil temperature of 11-30 and soil moisture of 20%-60%.

At the same time, the residue of pesticides on vegetables is reduced. In addition to pesticide control, reasonable fertilization is also very important, especially the increase of phosphorus and potassium fertilizer can effectively improve the disease resistance of crops and reduce the chance of disease. : Timely topping, timely removal of ineffective flower buds, pruning of ineffective branches and leaves, etc., can reduce premature aging and promote yield increase to a certain extent.

Apply organic fertilizer and biological fertilizer, apply fully decomposed organic fertilizer, reduce the single concentrated and large use of chemical fertilizer, and appropriately increase phosphorus and potassium fertilizer. New soil seedling or bed soil disinfection, mix well with 50% carbendazim wettable powder 5 6 kg of soil per mu, first sprinkle 1 3 medicinal soil on the furrow surface, and then sow it, and then cover it on the seeds with medicinal soil.

After the seedlings are fixed or planted, the growth is slow, and half of the leaves fade green, resulting in half or the whole leaf wilting, as if lacking water, pulling up diseased plants, few fibrous roots, cutting the main stem, and turning brown in vascular bundles. After the diseased strain is found, fungal fungicides should be used in time, such as 70% methyl tobuzine wettable powder or 64% alum.

There were no obvious symptoms on the leaves of the seedlings of Chinese cabbage yellow leaf disease, and the pathogen was infected by the root system at the 2 4 leaf stage, and the vascular bundle of the main root system turned brown and turned black after growing to the core stage. At the rosette stage, the leaves suddenly show symptoms of water deficiency, wilt during the day and recover at night, and the leaf veins turn brown at the centering stage, and the whole leaves shrink and curl inward due to water loss, which eventually leads to yellowing or death of the whole plant. The cabbage that forms the commodity value is harvested with shrunken leaves and reduced weight per plant, incomplete taproot system and brownish-black vascular bundles, and shortened storage time.

Chinese cabbage yellow leaf disease affects the growth of Chinese cabbage, the symptoms of Chinese cabbage yellow leaf disease are that at least half of the leaves are green and begin to degenerate, the whole leaf is wilted, it looks like a lack of water, and the diseased plant has few fibrous roots, and the vascular bundles turn brown.