How to control celery spot blight? What are the diseases of celery and what are the prevention and c

Celery is a vegetable commonly eaten in life, with good taste and high nutritional value, and can be cultivated in the open field in spring and autumn, and cultivated in facilities in autumn and winter. Recently, the temperature has been large, and the celery in the open field can be covered with plastic film and straw to prevent freezing, and if it is cultivated in a facility, attention should be paid to heat preservation. At the same time, celery spot blight is easy to occur in the environment of low temperature and high humidity, which is an important disease of celery cultivated in winter and spring facilities, which is common and can continue to harm during the storage and transportation period of celery, which has a great impact on the yield and quality of celery.

1. Correct identification of symptoms Celery spot blight, also known as leaf blight or late blight, may occur during the growth period of celery, mainly harming the leaves, petioles and stems of celery, the old leaves are diseased first, and then infected to the new leaves, scattering a lot of disease spots on the leaves, and the disease spreads quickly.

In the early stage of celery leaf infection, there are light gray-brown small spots, and then gradually spread and develop into irregular spots, with brown necrosis in the middle, obvious edges, and many small black grains are gathered, and the leaves will gradually scorch when the disease is serious. When the petiole and stem of celery are damaged, oblong, slightly concave brown lesions will appear, and small black spots will appear in the middle.

2. Pathogenesis of celery spot blight is a fungal disease, mainly with the help of mycelium to overwinter on seeds and diseased residues, and conidia will be produced when encountering suitable temperature and humidity conditions, which are spread through wind and rain and agricultural operations. In the process of celery planting, the spores of the disease will invade the old leaves and wounded leaves when the environment is low and high humidity, and then produce conidia to spread and spread after a few days of incubation.

Low temperature and high humidity are the main conditions for the occurrence of spot blight, and the temperature is 20-25 and the humidity is above 90%. If there are cloudy days, frequent temperature fluctuations, condensation at night, or untimely ventilation and moisture removal, it will aggravate the spread of the disease.

3. How to prevent and control the effect? First of all, pharmaceutical prevention and control. Once celery spot blight occurs, it should be sprayed, which can be controlled with 1500 times of amizeda and 1000 times of prochloraz, and can also be sprayed with 35-45 grams of 10% difenoconazole water-dispersible granules, 600-1000 times of 58% methamafen-manganese-zinc wettable powder or 600-1000 times of 70% ethyl aluminum-manganese-zinc wettable powder.

After applying the pesticide, track the control effect, if the control effect is not good, it should be changed and sprayed again once to effectively control the disease.

Second, control temperature and humidity. In the early stage of the disease, watering should be properly controlled, and attention should be paid to enhancing ventilation and reducing air humidity in facility cultivation; When the temperature changes frequently, it is necessary to pay attention to heat preservation and temperature control to avoid high and low.

Third, fitness cultivation. The implementation of crop rotation can reduce the number of pathogens in the field; Choose disease-resistant varieties, different varieties have different resistance, and choose disease-resistant varieties in areas with more diseases, and pay attention to disinfection before sowing; Reasonable dense planting, according to the celery variety to choose the appropriate planting density, conducive to ventilation and light transmission, celery growth robust; Strengthen water and fertilizer management, top dressing according to the growth of celery, and appropriate spraying of boron fertilizer to enhance plant disease resistance.

Celery should be sprayed in time, spot blight is caused by bacterial infection, and insecticides can kill bacteria very well.

Choose varieties that are highly resistant to disease. Use disease-free seed fields to select and retain seeds. Bacterial commercial seeds can be soaked in warm soup. In order to improve the disease resistance of celery and promote the healthy growth of celery, the organic matter content in the soil should be increased.

1. Soft rot.

It occurs mainly at the base of the petiole or on the stem. Water-immersed, light brown spindle-shaped or irregularly shaped depressed spots first appear, then wet rot, black and smelly, leaving only the epidermis. Pathogenic bacteria overwinter in the soil, invade from wounds, spread through rainwater or irrigation water.

The disease is severe when the humidity is high, and sometimes it is mixed with frostbite or other diseases. Prevention and control measures: the implementation of crop rotation for more than 3 years; Avoid root damage when transplanting, loosening or hoeing; Timely drainage after rain; If the diseased plants are found, they should be dug up in time and sprinkled with lime for disinfection; reduce or suspend watering during the onset of the disease; At the beginning of the disease, 72% agricultural streptomycin sulfate 3000 times liquid spray was used for prevention and control, sprayed once every 7-10 days, and continuously prevented limb destruction and treatment 2-3 times.

2. Spot blight.

Mainly harms the leaves. At the beginning of the disease, the leaf lesions are round or irregularly shaped, with obvious edges, yellowish-brown, grayish-white, and scattered black dots. The disease is severe when it is cold, humid, rainy, or when the plant is weak.

Control measures: strengthen field management, apply foot fertilizer, reasonable top dressing, and enhance plant disease resistance; It is necessary to pay attention to cooling and dampness, reduce the temperature difference between day and night, reduce condensation, do not use large water for flood irrigation, and use dark irrigation under the membrane; At the onset of the disease, 5% chlorothalonil dust agent can be sprayed, 1 kg per mu each time, or 75% chlorothalonil wettable powder 600 times liquid and 60% amber. 500 times of ethophosphine aluminum wettable powder and 500 times of 47% Garinone wettable powder, once every 7-10 days, 2-3 times of continuous control.

3. Sclerotinia sclerotiorum.

It mainly harms celery stems and leaves. The affected part is brown and water-soaked at first, and when the humidity is high, soft rot is formed, and white hyphae are born on the surface, and then a black sclerotia of mouse feces is formed. The germination temperature of sclerotia is 5 -20 and 15 is the most suitable, and the disease is prone to occur and epidemic when the relative humidity is more than 85%.

Control measures: 3-year crop rotation; At the beginning of the disease, spray 50% Sukrin or 50% promethine or 70% methyl tobuzin residue 600 times or 50% carbendazim wettable powder 500 times. After the onset of the disease, spray 5% chlorothalonil dust agent, 1 kg per mu each time.

4. Viral diseases.

The whole celery plant can be infected with viral diseases. The initial leaves are shrivelled and appear as thick, pale green mottled or yellow patches, which appear as distinct yellow spot mosaic leaves. In severe cases, the leaves of the whole plant are shrunken and not long, or yellowed and dwarfed.

The virus is mainly transmitted by aphids in the field, but it can also be transmitted by manual contact and friction. Poor cultivation and management conditions, drought, and the number of aphids are frequent and serious. Prevention and control measures:

Do a good job in the prevention and control of aphids, and use yellow plates to trap and kill; Strengthen fertilizer and water management, promote plant growth and robustness, and improve plant disease resistance; Foliar spraying can also improve disease tolerance; At the beginning of the disease, spray 1000 times of phytolingl emulsion or 500 times of 20% virus A wettable powder.

Celery spot blight, also known as leaf spot and late blight, is a common disease of celery in winter and spring protected areas, which has a great impact on the yield and quality of celery. It mainly harms the leaves, followed by petioles and stems. To balance fertilization, the bottom fertilizer should be applied with well-rotted organic fertilizer, and try to spray some foliar fertilizer and micro-fertilizer to enhance the resistance of the plant.

Cooling and dampness, reducing condensation, do not flood irrigation and chemical prevention.

Due to the large planting area, celery, which used to have fewer pests and diseases, has also suffered from pests and diseases due to the overly rough planting management model. The celery spot blight introduced by Li Nong today is one of the most common, most harmful, rapidly spreading and frequent diseases in the process of celery planting and production. If this disease occurs, celery production will be reduced by 20 to 30 percent, and in severe cases by more than 50 percent, and even lead to the loss of pre-war commerciality.

Ranunculus spot blight, also known as leaf blight, mercenaries in the mountainous areas of our country have occurred in the open air planting and facility planting, the harm to parsley, parsley is greater, the harm to parsley is relatively small. This disease mainly affects the leaves, petioles and stems of celery, and forms or forms small spots on plants at the time of onset, most of which are large spot blight in southern China and small spot blight in northern China. Prevention and control:

Celery is also a cold-climate crop, so the occurrence, spread, and spread of the disease can only be avoided by regulating moisture, regulating humidity, and enhancing lighting.

It shows that the soil is particularly moist and has not seen sunlight for a long time, so celery will get spot blight, and celery has spot blight that particularly affects the output value, and the remedy is to use some pesticides.

Celery spot blight, also known as leaf blight, late blight, commonly known as fire dragon, is a common and serious disease on celery, this disease can continue to occur during storage and transportation, and the pathogen is a fungal control method: Select disease-free seeds or seed disinfection: When the seeds are collected from disease-free plants or used for more than 2 years, the seeds should be disinfected, and the method is the same as that of celery spot disease Agricultural measures:

Remove the diseased residues in the shed, concentrate on manure or deep burial, remove the diseased leaves at the beginning of the disease, reduce the source of pathogens and strengthen the cultivation management, and enhance the disease resistance of the plant Ventilation cooling and humidification: the shed should pay attention to the ventilation to cool down and reduce humidity, which can control the occurrence of diseases during the day The temperature of the shed should be controlled at 15 20 degrees Celsius, and the temperature should be released in time when it is higher than 20 degrees Celsius, and the night temperature should be controlled at 10 15 degrees Celsius, so as to reduce the temperature of day and night, reduce condensation and prevent flood irrigation Pesticide control: When celery seedlings are 2 3 cm high, spraying protection should be started, After that, spray every 7 to 10 days.

You can use 75% chlorothalonil wettable powder 600 times liquid, or 64% alum wettable powder 500 times liquid, or 65% zeb wettable powder 500 times liquid, or 1 times Bordeaux liquid, or 50% sulfur suspension 200 300 times liquid, spray once every 7 10 days, a total of 2 3 times can also be used 45% chlorothalonil fume, the dosage per mu is 200 230 grams, or spray 5% chlorothalonil dust agent, the daily dosage is 1000 grams.

Symptoms: Mainly damage the leaves, but also the petioles and stems, the leaves are diseased, at first light brown oily spots, and then develop into yellow-brown to black-brown ring dead spots, the lesions are generally larger, nearly round, the edges are dark green, and the lesions are scattered with black spots. The petioles and stems are infected, mostly forming fusiform brown necrotic spots, depressed, infiltrated edges, and scattered black dots in the diseased parts.

When the disease is severe, the surface of the plant is covered with diseased spots, necrosis and dryness.

Control methods: Choose disease-free seeds with disease-free plants, or use alternate-year seeds. Ordinary seeds should be soaked in warm soup, which can be soaked in 48 50 warm water for 15 minutes and 20 minutes, stirring while soaking, and then cooled with cold water, and sown after drying.

After harvesting, remove the diseased leaves in the field, take them to the field for deep burial and destruction, and remove the diseased leaves in time at the early stage of the disease.

Choose resistant and disease-resistant varieties.

Strengthen management during the growing season, increase the application of base fertilizer, and timely drainage after rain. Pay attention to ventilation and moisture drainage, reduce condensation at night, and prohibit flood irrigation.

In the early stage of the disease, pharmaceutical prevention and treatment should be carried out. When the celery in the protected area is sick, 5% chlorothalonil dust agent can be sprayed, 1 kg per 667 square meters each time, and 75% chlorothalonil wettable powder 600 times can be sprayed in the open field, or 60% amber ethylphosphine aluminum wettable powder 500 times or 47% Garinon wettable powder 500 times, once every 7 days and 10 days, 2 times and 3 times for continuous control.

Celery spot blight, also known as leaf blight, is the main disease of celery, and celery is the most affected in the protected land. Celery in the open field suffered heavily from summer-sown celery.

Symptoms: Celery can be infected in the aboveground parts. The leaves are infected with the disease, at first it is a water-stained light yellow nearly round small spot, and gradually develops multiple lesions together, forming large patches with obvious edges and irregular shapes, and later the diseased part fades green to gray-white, and scatters many raised small black spots (color edition 18, 104). The petioles and stems are infected, the lesions are grayish-white, oblong, slightly concave, there are yellow halos on the edges of the diseased parts, and there are many raised small black spots on the diseased parts.

The pathogen belongs to the genus Acenospora spp. The conidia are buried under the epidermis. The spores are colorless and transparent, long linear.

Lethal temperature of mycelium and conidia 48-49, 30 min. The germination temperature of conidia was 9 28, higher than 27, and the development was slow.

Pathogenesis. The fungus overwinters in the soil with mycelium in the seed coat or attached to the diseased residue. The pathogens overwintering in the seed coat cause disease at the seedling stage and spread in the seedling furrow. The pathogens that overwinter with the diseased residues in the soil produce conidia and conidia when the conditions are suitable, which are spread by air currents and rainwater.

The cool climate and high humidity environment are conducive to the onset of the disease. The optimal temperature for the onset of the disease is 20 25, and the optimal relative humidity is more than 95%. Therefore, continuous rain, low temperature, large temperature difference between day and night, long condensation time and weak plant growth are all conducive to occurrence and epidemic.

Prevention and control methods. 1) Choose disease-free seeds, or use the characteristics of pathogenic bacteria to survive in the seed coat for about 1 year, and choose the seed that has been stored for 2 years.

2) Soak seeds in warm soup. Soak the seeds in 48 warm water for 30 minutes, remove and dry to sow seeds.

3) Strengthen field management. Adjust the sowing date appropriately; Avoid flood irrigation, cultivate and drain water in time, and pay attention to wind and humidity to control its occurrence.

4) Pharmaceutical prevention and control. Spray with 50% chlorothalonil smoke agent 250 grams per 667 square meters or 5% chlorothalonil dust per 667 square meters 1 kg or 75% chlorothalonil 600 times liquid or 70% methyl tobuzine 600 times liquid or 50% promethine 1000 times liquid liquid.