What s the deal with celery pseudomelasma? What kind of medicine can be used to prevent it?

At the beginning of the onset of Bain, light brown spots in the shape of water stains, in the form of circular necrotic spots, yellowish-brown, dark brown, with dark and vivid edges, the size of the spots develops to 6 8 mm. The lesions are easy to crack and break, and when the air is humid, a rare black fungus appears in the middle. Celery black spot disease is an accumulated temperature of 17 20, high temperature Dow high humidity is serious, and the disease develops rapidly.

The heat is dry and hot, but it is easy to get sick at night when the dew is condensed. In particular, water shortages, insufficient fertilizers, too much water addition, or poor plant growth are serious.

Implement crop rotation for more than 2 years, remove diseased leaves, remove diseased plants and diseases during the growth period, and deal with them intensively. After harvesting, the disease is completely removed and the soil is deeply turned. To select excellent disease-resistant varieties, the seeds should be dried before sowing, and then the new plastic film needle-free seeds should be used to avoid underground pests and diseases, isolate virus infection, not affect the germination and swelling function, enhance the respiratory intensity, and improve the germination rate of seeds.

Fully apply sufficient basic fertilizer, carry out topdressing in a timely manner, and carry out weeding in Chongqing to prevent premature plant aging. Watering in the protected area should be selected in the morning on a sunny day, increase the ventilation after sprinkling, and drain water in time after rain to prevent high temperature and high humidity. Before or at the beginning of the disease, spray 50% purple servant humidification powder 1500 times, 58% methyl frost annular manganese-zinc humidification powder 500 times, 75% white fungus clear humidification powder 600 times, 80% Dasheng humidification powder 800 times, 40% sterilized Dan humidification powder 400, or the warehouse room in the early stage of the disease can use 45% white fungus green smoke, 250 grams per mu, spray a new high-fat film 800 times liquid, consolidate the prevention effect, 9 11 days a smoke 2 3 times in a row.

This disease mainly harms the leaves, and the old leaves are more susceptible to disease. Leaf injury indicates that after the onset at the leaf edge and petiole is the disease, it slowly spreads throughout the leaf. Early infection gives the leaves a yellowish-green watery patch, which later develops into round or irregular shapes with spots about 2 15 mm in size and grayish-brown in color.

When the disease is severe, the lesions will turn into spots, and the entire leaf will turn yellow or even wilt. Stems and petioles can also be harmed. At the beginning, the yellow color gradually turns gray-brown, the stems are broken, the celery is poured, and when the humidity of the growing environment is relatively high, there will even be a large area of corruption.

After the onset of the disease, leaf cotton, leaf cotton, etc. have gray-white fungal layers, which are all pathogens.

Nighttime work sickness is most likely to occur in high temperature and humidity environments. The suitable survival temperature of the pathogen is 25 to 30 degrees, and the spore germination temperature of the pathogen is 28 degrees. With the recent increase in temperature, the temperature of the greenhouse is more suitable for the growth and reproduction of germs, so it is necessary to pay attention to regulating the temperature.

On rainy days, the relative humidity may be high, and spores can be formed, causing recurrent infections. After the rain, the weather suddenly becomes hot and clear, and the disease will develop to an uncontrollable degree, causing a large area of celery to die and collapse one by one. In addition, due to the environment that is prone to illness, high temperatures and droughts, and dew condensation at night, this situation is also relatively easy to develop.

The germ of celery pseudo-black spot overwinters with the diseased residues left in the soil and is transmitted to the plants the following year by wind or rain splashing. The pathogen development of pseudomelanoma is suitable for temperature 25 30. The optimal temperature for conidia formation is 15 20, and the appropriate temperature for germination is 28.

High temperature and rain or high temperature and drought, but the dew condensation is heavy at night, the duration is long, and it is easy to get sick. In particular, there is a serious incidence of water shortage, lack of fertilizer, excessive irrigation or poor plant growth.

Celery black spot is also known as pseudo-black spot, and the occurrence site of celery black spot is near the surface of the root neck and the base of the petiole, and the root can sometimes be damaged. The main symptom is that the diseased area becomes dark and rotten, and many small black spots grow on it, and these small black spots are called conidia. The diseased plants are short and weak, and the 1 to 2 layers of petioles on the periphery of the plant are easy to fall off due to the rot of the bottom.

The lesions are nearly round, dark brown, with clear edges, 6-8 mm in size, sometimes occurring on the leaf margins, and there is sparse black mold in the middle of the lesions, which is easy to crack and break.

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.

Prevention and control methods of celery spot blight: (1) Choose disease-free seeds. Seeds are harvested from healthy plants in disease-free fields.

2) Seed disinfection. Before sowing, the seeds were soaked in warm water at 50 degrees Celsius for 20 minutes, stirred constantly, and immediately moved into cool water to promote germination and sowing.

3) Strengthen field management. Apply sufficient basal fertilizer, apply more organic fertilizer, appropriately increase phosphorus and potassium fertilizer, improve plant disease resistance, use water reasonably, and avoid flood irrigation. Remove the sick and disabled bodies in time, concentrate on treatment, and reduce the source of bacteria.

The temperature should be controlled at 15 20 degrees Celsius during the day, and the ventilation should be timely when it exceeds 20 degrees Celsius, and it should be controlled at 10 15 degrees Celsius at night, so as to narrow the temperature difference between day and night, reduce condensation, and reduce the incidence of disease.

4) Pharmaceutical prevention and control. At the beginning of the disease, spray 600 times of 75% chlorothalonil wettable powder, or 64% alum, or 500 times of 40% polysulfur suspension, once every 7 10 days, spray 2 3 times. 200 250 grams of 45% chlorothalonil smoke can be used for every 667 m2 of the shed protected area, and the control effect is good.

Select disease-free seeds, and soak seeds in warm water at 48 to 49 degrees Celsius for 30 minutes Apply foot fertilizer before sowing, and look at the seedlings for top dressing; At the beginning of the disease, 5% chlorothalonil powder should be sprayed in time 1 kg mu (seedling stage), or 75% chlorothalonil 600 times liquid, or 64% alum 500 times liquid 2 3 times, with an interval of 7 10 days.

Celery spot blight is also known as leaf blight. Celery leaves, petioles, and stems can be infected. One of the sedan cars is the first disease of the old leaves.

It is then transmitted to new leaves. The leaves are scattered with stupid slippery spots, varying in size, 3-10 mm in diameter, small spots of light brown oily stains at first, and then gradually expanding, the middle part is brown necrosis, the outer edge is mostly dark reddish-brown and obvious, and a small number of small black spots are scattered in the middle. The other, at the beginning, is not easy to distinguish from the former, and the latter ** is yellowish-white or off-white.

There are many small black spots on the edges, and there is often a yellow halo on the outside of the lesion, and the diameter of the lesion varies. The petiole or stem is infected, the lesion is brown, oblong and slightly concave, and the middle is scattered with small black spots.

Prevention and control methods: 1. Select disease-free seeds or disinfect diseased seeds. Collect seeds from disease-free plants or use old seeds that have been stored for 2 years, if new seeds are used, they should be soaked in warm soup, that is, 48-49 soaked in warm water for 30 minutes, stirred while soaking, and then moved into cold water to cool, dry and sow seeds.

2. Strengthen field management, apply foot fertilizer, look at seedlings and top dressing, and enhance plant disease resistance.

3. Cultivated in protected areas should pay attention to cooling and exhaust temperature, control the temperature during the day to 15-20, and control the wind in time if it is higher than 20, and control it at 10-15 at night, so as to narrow the temperature difference between day and night, reduce condensation, and avoid large and small flood irrigation.

4. When the celery seedlings in the protected area are 3 cm tall and may develop the disease, apply 45% chlorothalonil fumigant, dosage: 200-250 grams per mu, or spray 5% chlorothalonil dust agent, 1 kg per mu. In the open field, you can choose to spray 600 times of 75% chlorothalonil wetting powder, 500 times of 60% succinphosphine aluminum wettable powder, 500 times of 64% alum wettable powder, and 500 times of 40% polysulfur suspension, and spray 1 time every 7-10 days, 2-3 times in a row.