Control techniques of cucumber diseases and insect pests in greenhouse
China Vegetable Network Source: China Tianmen Reading Number: 2352
Moderator: With the development of protected cultivation, people can still eat fresh and delicious cucumbers in winter. However, in the process of cucumber planting and production, it will still be attacked by various pests and diseases, especially in winter. It's not easy to bear a straight and sweet melon. It is necessary to overcome the bad weather conditions in cloudy and snowy days, coordinate temperature, light, water and fertilizer, and cultivate a high-quality cucumber to sell at a good price. We asked Mr. Jiang Jingyu, an agricultural technology extension researcher at Hebei Plant Protection Station, to introduce the diseases and insect pests that are easy to occur in cucumber growth period and their control techniques. Now Teacher Jiang has come to the studio. Hello, Teacher Jiang!
Expert: Hello everyone!
1. Moderator: Mr. Jiang, many farmers grow cucumbers in greenhouses in winter, hoping to get a good price during the Spring Festival, but there will be some problems in the anti-season planting process. What are the basic management of cucumber planting in farmers' greenhouses?
Expert: The management of cucumber planting in winter is mainly temperature management. In addition, it is necessary to water according to local conditions and apply fertilizer in a timely and appropriate manner. Farmers' friends mainly focus on the following nine aspects:
(1) accelerate germination. Soak the seeds in warm soup, control the temperature at 28 ~ 30℃, and accelerate germination for 24 hours until more than 70% of the seeds are exposed.
(2) Raising seedlings. Add a small arch shed (or greenhouse electrothermal hotbed) to raise seedlings. The sowing amount per mu is about 0. 1 kg, the seedling age is 40-45 days, and the indoor temperature in the shed is guaranteed to be 20-25℃ during the day and 16℃ at night.
(3) Colonization. When the plant height is 17 ~ 20cm, the stem is stout, with 5 ~ 6 true leaves, and 60% plants can grow female flowers.
(4) Slow seedling. The shed should be closed, and the temperature should be controlled at 28 ~ 30℃ during the day and 20 ~ 22℃ at night.
(5) Entering the early flowering stage. It can be ventilated at 22 ~ 25℃ during the day, and at night, 13 ~ 15℃ shall not be lower than 10℃.
(6) the temperature of the fruiting period. Ensure that it is 25 ~ 30℃ in sunny days, 14 ~ 15℃ at night, and it is lower than 2 ~ 3℃ in cloudy days.
(7) Other management. Mainly pay attention to the pruning of tea racks, and tie rattan to make the faucets arranged in a diagonal line with high in the south and low in the north. When the plant grows to 25 leaves, core is taken.
(8) moisture. After planting for a week, slowly water the seedlings, and squat down the seedlings after the root melons sit down. Root melon 15 cm, squat down. Pour some water. Water the root melon once after harvest, and then keep it moist.
(9) Fertilization. Topdressing the root melon after harvesting, and spraying 0.3% potassium dihydrogen phosphate and 0.5% urea on the leaves in the middle and late stage.
2. Moderator: Manager Jiang, you often encounter some threats of pests and diseases in the process of planting yellow rice. What diseases and pests will cucumber encounter in the whole physiological process?
Expert: The main diseases and pests of cucumber are damping off, damping-off and physiological retting at seedling stage. Diseases that often occur in adult stage include downy mildew, angular leaf spot, epidemic disease and so on. In winter, various physiological diseases, such as melon topping and bitter gourd, which affect the growth of plants and melon strips, are prone to occur. Therefore, it is necessary to effectively control the diseases and insect pests in cucumber growth period.
3. Moderator: It seems that in the process of cucumber planting, farmers should pay attention to disease prevention and treatment. Teacher Jiang, can you tell us something about the occurrence of diseases at seedling stage?
Expert: seedling diseases are generally easy to occur in the roots. Every year, from 65438+February to 65438+1October, vegetable seedlings are raised. If the weather conditions are not ideal at this time, the seedlings are easy to be infected with damping-off disease, leading to lodging and death. The symptom of damping-off disease is that the stem base or middle part of cucumber seedling contracts into a line, and the plant quickly falls on the seedbed until the plant dies. Rice sheath blight mainly causes seeds and buds to rot, and round dark brown spots appear at the base of buds, which makes cotyledons wither during the day and the diseased parts atrophy and die, standing but not falling.
4. Moderator: These two diseases are very harmful to cucumber seedlings. How to prevent them in advance?
Expert: For seedling diseases, we should focus on prevention. Farmers should pay attention to four points:
(1) Seed disinfection and bed soil disinfection. Soak melon seeds in warm water at 55℃ for 10 ~ 15 minutes, stir constantly, cool and soak in warm water at 30℃ for 6 hours, then disinfect with 10% trisodium phosphate for 30 minutes, scrub with saturated lime water for 3-5 minutes, and finally rinse with clear water for 3 times. Pick up the seeds, pinch them with a dry towel or dry them. The purpose is to kill the germs carried by seeds, such as epidemic disease, virus disease, anthracnose, Fusarium wilt, angular leaf spot and so on.
(2) Bed soil: use 0.5 kg of 50% carbendazim per mu, add fine dry soil 100 kg, stir evenly, and cover the seeds.
(3) Post-seedling management: Spraying 10% Amisi 1500 times solution and 2% Haopu 500-800 times solution to prevent diseases.
(4) Early onset: If the seedling is infected with Rhizoctonia solani, use 98% hymexazol wettable powder 3000 times, 64% antiviral alum wettable powder 600 times, and 50% carbendazim wettable powder 600 times for 2-3 times continuously. Once every 7 ~ 10 days. Spraying 50% carbendazim wettable powder and 70% mancozeb 600 times solution after damping off. When damping-off and damping-off are mixed, 800 times of 72% thiram aqueous solution and 800 times of 50% thiram aqueous solution are sprayed.
5. Moderator: Farmers' friends must pay attention to the prevention and management of seedling stage to avoid the invasion of germs. Teacher Jiang, what should I do if there is a stiff seedling at the seedling stage?
Expert: Cucumber seedlings are also prone to retting, which shows that the roots rot without new roots and the leaves are yellow and brown. In addition, it is easy to appear stiff seedlings, which is characterized by less leaves and roots.
The main reason of seedling stiffness is that vegetable seedlings are in low temperature environment for a long time.
The solution to the stiff seedlings of retting roots is to increase the temperature in the seedling shed, which can be improved by means of hotline, lighting and small arch shed. In addition, spraying 6000 times brassinolide on leaves, or collecting 6000 times more liquid and 400 times more nucleotide foliar fertilizer can promote root growth and make seedlings grow back to normal.
6. Moderator: Teacher Jiang introduced us to seedling diseases. Many diseases will occur in adulthood, which directly affect the yield of cucumber. Please tell us again.
Expert: OK, first of all, let's introduce downy mildew, which is the most important disease of cucumber. Downy mildew is a high temperature and high humidity disease, which is also called galloping horse stem because of its rapid onset. Generally, it is serious in March-April in spring, with polygonal brown spots, green mesophyll, limited by veins, and gray-black (purple-black) bacteria layer on the back of leaves. Causes the leaves to dry up and fall off quickly until the plants die.
Control method of downy mildew: (1) Using high-temperature closed shed is one of the important means to control diseases in greenhouse, which can be used to control downy mildew, powdery mildew, angular leaf spot, gray mold, scab and other diseases. The specific method is to close the greenhouse around noon on a sunny day after pouring water to raise the temperature. When the temperature reaches 45 ~ 46℃, keep it at 1.5 ~ 2 hours, and then slowly ventilate to cool down. Note that when the greenhouse is closed, the mercury ball of the thermometer should be on the same level as the highest point of the plant. You can also water the shed the day before closing, and then water it after closing.
(2) Chemical control: 700-800 times of 66.8% Modoco wettable powder, 75% Kekangling 1500 times of liquid, 300 times of sugar and vinegar were added to control downy mildew; When angular leaf spot occurs, 400 times of 77% bactericide wettable powder is added. In recent years, new drugs such as imported new drug 10% Kejia suspension concentrate have been used to control downy mildew of cucumber, melon and grape. Generally, spray 2 ~ 3 times, 2000 times of solution after slow planting, with an interval of 7 ~ 10 day. It can also be used as a therapeutic agent. At the initial stage of the disease, 1 0,000 ~10,500 times solution was used for 2 ~ 3 times, with an interval of 7 ~ 10 day. The duration of this medicine is 10 ~ 14 days, and the effect is not affected by rain after application. It can be mixed with most pesticides and fungicides, such as 500 times of 53% Jin Lei solution, to increase internal absorption conductivity.
In addition, the 42% trichloroisocyanuric acid soluble powder popularized in recent years is also a new eradicator for preventing and controlling downy mildew of vegetables. The trade name is Ke Junjing. It is a broad spectrum, systemic and therapeutic fungicide. Cucumber downy mildew was sprayed with 3000 ~ 4000 times solution and 0.5% amino oligosaccharide aqueous solution (os- Sterling) with 1000 times solution, which not only cured the disease, but also improved the immunity of plants. When spraying the liquid medicine, it must be sprayed evenly and thoroughly, so that the leaves carry the medicine. After spraying, check whether the layer of Phytophthora infestans is dry. Generally, it should be used for 2 ~ 3 times.
7. Moderator: You just said that angular leaf spot was mentioned in the prevention and control, which is also a disease that harms cucumber. How to prevent cucumber from angular leaf spot?
Expert: angular leaf spot is a chlorosis spot with yellow protrusion on the front of the leaf and a bacterial membrane with water stains on the back of the leaf. The diseased spots on the back of the leaves are polygonal with water stains on the edges. In the later stage of drying, the center of the lesion dries up and falls off into a hole, and when it is wet, it produces milky white fungus pus, which forms a layer of white powdery substance after evaporation, or leaves a layer of white film. The diseased spots on the stems and petioles of melon are nearly round, waterlogged and have white pus on the surface, which turns light gray in the later stage and cracks appear in the middle.
Here we should pay attention to distinguish between angular leaf spot and downy mildew. The difference between angular leaf spot and downy mildew is that the lesion on the back of downy mildew leaves generally has a black or purple mold layer, and the lesion is not perforated in the later stage, so that the melon strips are not damaged; The back of angular leaf is infected with bacterial pus, the lesion will be perforated, the melon sticks will be damaged, and there is a bad smell.
Four points should be paid attention to in the prevention and treatment of angular leaf spot:
(1) Implement crop rotation. Rotation with non-host crops at intervals of 2 ~ 3 years can reduce the incidence and harm.
(2) Do not keep or treat diseased plants. Choose gardens or fields where cucumbers have never been planted to breed seeds. If you breed seeds in a garden where cucumbers have been planted, choose plants that are disease-free to preserve the seeds. Seeds sold in the market must be treated before sowing, soaked in 500 times of 50% amobam aqueous solution for 65438 0 hours, washed with clear water after taking out, and germinated before sowing. Seeds can also be soaked in 200ppm phytomycin 1 hour, drained and soaked in clear water for 3 hours to accelerate germination and sowing. In the absence of chemical substances, the seeds were soaked in warm water at 55℃ for 65438 05 minutes, and then soaked in cold water for 4 hours to accelerate germination and sowing.
(3) Strengthen cultivation management. Cultivate disease-free seedlings, use new disease-free soil seedbeds to raise seedlings, release air in protected areas in time, reduce humidity in the shed, control irrigation after illness, promote root development and enhance disease resistance, and remove diseased plant residues after harvest to reduce harm. 4. Chemical control. If the plant gets sick, spray 4000 times of agricultural streptomycin or 4000 times of neophytomycin at the initial stage. Or spray 30% DT disinfectant for 500 times.
8. Moderator: Besides angular leaf spot, are there any other bacterial diseases of cucumber?
Expert: Mainly bacterial leaf blight and bacterial edge blight. Bacterial leaf blight has occurred from time to time in recent years. The symptoms of this disease are easy to identify. It mainly harms leaves, with faded yellow-green spots on the front and water-soaked faded spots on the back. The lesions are thin, white, grayish white, yellow and brown. Sometimes dry pus can be seen on the back of diseased leaves. The young stems are infected and the diseased stems are cracked. Round gray spots are formed on the fruit, among which there are yellow dry fungus pus.
Bacterial edge blight spreads upward from the lower leaves of plants. Most lesions develop inward from the leaf margin, forming a "V"-shaped serious disease, which is gray or light brown. And gradually become withered spots along the leaf edge, and some diseased spots appear in other parts, which is also irregular. The lesions are rarely cracked or perforated, but crisp and dry. The lesions on stems, petioles and tendrils are brown water stains. After dehydration from the handle, the melon sticks began to appear brown waterlogging, wilting and stiffness, and when the air humidity was high, the affected parts overflowed with pus.
To prevent bacterial blight and bacterial edge blight, the seeds should be disinfected first to kill the germs that may be carried on the seeds. Before sowing, soak the seeds in warm water at 55℃ for 20 minutes, take them out to dry, then accelerate germination or sow, or soak the seeds in 800 times potassium permanganate solution 15 ~ 20 minutes. Or 654.38+00000 units of agricultural streptomycin 500 times solution for 2 hours, washing, accelerating germination and sowing.
Secondly, the humidity in the greenhouse is controlled, and the water supply mode of under-film irrigation or drip irrigation is adopted to reduce the relative humidity. After the onset, some diseased leaves with no function at the lower part can be removed and buried deeply. Thoroughly dispose of the residue after pulling out the vegetable garden. At the early stage of the disease, spraying the medicine in time, and using 77% gram to kill 500 times of wettable powder, 12% green milk copper EC 500 times of liquid, 47% lennon wettable powder 500 times of liquid, and 20% dracunculus water suspension concentrate (clothianidin copper). Spray is 600 times that of liquid. Once every 5 ~ 7 days, and used continuously for 3 ~ 4 times.
9. Moderator: There is another disease in cucumber cultivation called anthracnose. What should we pay attention to when suffering from this disease?
Expert: Anthracnose, which forms round lesions on stems and petioles, is first soaked in water, light yellow, and then turns dark brown. When the leaves are damaged, small water-soaked spots appear at the initial stage, and then expand into nearly round spots, reddish brown, with obvious yellow halo at the edge of the spots. When there are many spots on the leaves, they often merge into irregular large spots. There are many small black spots on the lesions in the later stage, which grow pink mucus when wet, and are easy to rupture and form perforations in the middle of the lesions when dry. At the onset of melon strips, a round light green concave lesion with black spots was formed on the surface, and a pink sticky substance was produced on the surface of the lesion in the later stage.
The cause of anthracnose is the disease in the soil and bacteria carried by seeds. Prevention and control methods:
(1) Selection of disease-resistant and disease-free varieties.
(2) Soak the seeds with warm water at 55℃ for 65438 0 5 minutes before sowing. You can also soak the seeds in 500 times solution of 50% carbendazim wettable powder for 60 minutes, and then rinse the seeds with clear water.
(3) Strengthen shed management, keep fresh air to prevent moisture, control temperature and prevent diseases, generally control it at about 30℃ in the morning, and keep fresh air properly in the afternoon and evening.
(4) Chemical control: use 45% chlorothalonil smoke agent, 250g per mu. Powder: spray 5% chlorothalonil powder or kemeiling powder per mu 1 kg; 700 times of 50% thiophanate methyl wettable powder and 200 times of 75% chlorothalonil wettable powder, or 800 times of 80% anthrax thiram wettable powder or 500-600 times of 65% mancozeb wettable powder, or 400 times of 70% mancozeb wettable powder, or 200 times of 2% antifungal agent 65,438+00%. At the same time, foliar fertilizer was added to make the leaf growth return to normal.
10. Moderator: In cucumber planting, we often see some white hairs on the leaves. What disease is this and how to prevent it?
Expert: This is powdery mildew, also called "white hair" disease, which is easy to get sick on cloudy days. Powdery mildew mainly harms leaves, petioles, stems and vines, but does not harm fruits. At the beginning of the disease, white spots appeared on the front and back of the leaves, and then the connection was expanded and covered with a layer of white mold. White mold has irregular edges and then turns gray. Sometimes small black spots are produced on the diseased spots. Leaves gradually turn yellow, brittle and dry. Generally, it starts from the bottom leaf and gradually develops upward.
At present, powdery mildew pathogens have developed resistance to fungicides such as carbendazim and thiophanate. It should be noted that Fenxiuning is used to control powdery mildew on cucumber, and it will cause serious phytotoxicity if it is not paid attention to, so it is generally not used. Prevention and control methods:
(1) Chlorothalonil fumigant fumigation.
(2) 30 ~ 50 times of high-fat membrane can be used to prevent the disease; At the initial stage of the disease, 100 units of Nongkang 120, 20% antifungal 200 times solution, 10% sego 1500 times solution and 40% DuPont Fuxing 5000 times solution can be used; Fenbiqing wettable powder 1000 times solution; 600~80O times of 47% Garidone, the above drugs are used in rotation, and sprayed continuously for 3 ~ 4 times every 7 ~ 10 day/time.
1. Moderator: How to control cucumber gray mold?
Expert: Botrytis cinerea is a low temperature and high humidity disease. It mainly harms young melons, leaves and stems. The sick minister has long gray hair. Most of the germs invade from the abortive female flowers, causing the petals to rot, growing a gray-brown mold layer, and then spreading to the young melons, causing the navel to be waterlogged, and the young flowers quickly become soft, atrophy and rot, and the surface is covered with mold layers. When a large melon is killed, the tissue first turns yellow to produce gray mold, then the mold layer turns light gray, and the damaged part of the killed melon stops growing, rotting or falling off. Leaves are generally attached by fallen rotten flowers or diseased vines, forming large spots with a diameter of 20 ~ 50 mm, nearly round or irregular, with obvious edges and a small amount of gray mold on the surface. Rotten melons or rotten flowers can also cause stem rot, and in severe cases, the lower nodes rot, leading to vine fracture and plant death.
Control methods of gray mold:
(1) Control the temperature in the shed, raise the temperature to 25 ~ 30 degrees as far as possible, do not water on cloudy days, advocate using small water under the film to irrigate the water supply, and hoe away moisture on sunny days. Remove the diseased melon in time after the occurrence of gray mold, take it out deeply, and burn the residue after pulling out the seedlings.
(2) After the onset of the disease, 40% Shijiale Suspension Concentrate 800 ~ 1000 times, Telik 600 ~ 800 times, Kedeling 65% 1000 times, and Moxifabao 60% ultrafine powder 600 times were sprayed every 7 days.
2. Moderator: What disease is cucumber Fusarium wilt and how to prevent it?
Expert: Epidemic disease, commonly known as dead seedlings or dead vines, is a serious and uncontrollable disease. Wet rot at seedling stage mainly occurs at stem base, which often leads to cucumber Miao Qing wilt and death. The aboveground parts of melon seedlings will be damaged in the adult stage. The stems were oily at first, and then softened and contracted, resulting in wilting and even death of the stems and vines above the disease area. Fruits are more diseased than those near the ground. The diseased parts are oily depressions at first, and then quickly rot and grow white hairs. Mixed with saprophytic bacteria, it smells like fish. Leaf diseases are dark green and oily, with large, amorphous and inconspicuous edges. When wet, the diseased spot expands rapidly, causing the whole leaf to rot. Spreading to petioles and stems will cause diseases in this part. When the air is dry, the lesion is bluish white or light brown, which is fragile when it is dry. The onset can be affected by several diseases at the same time. But the vascular bundle of stem does not change color, which can be distinguished from Fusarium wilt. Melon stripe disease is oily and obviously sunken, which can be distinguished from soft rot and Sclerotinia sclerotiorum
Prevention and control methods of epidemic diseases: (1) Remove diseased melons in time and bury them deeply. (2) Preventive medication: After the slow seedling planting, use 10% Kejia suspension with 2000 ~ 2500 times of solution, with an interval of 7 ~ 14 days, divided into two times. In the disease center, 10% Kejia suspension 1000 ~ 1500 times, 58% Daphne manganese zinc wettable powder 500 times, 64% antiviral alum wettable powder 400 ~ 500 times, and 72.2% aqueous solution 600 ~ 700 times.
3. Moderator: Mr. Jiang, cucumber is prone to scab during its growing period. How did this disease happen and how to prevent it?
Expert: Because cucumber has weak resistance to scab at low temperature, it is more likely to occur when it is cold and humid. Scab pathogen mainly infects the growth point of cucumber, and dark green water spots appear on the leaflets, which expand into brown and break into star-shaped stomata. When the disease is serious, the vines stop elongation, there is glue on the cucumber branches, and the diseased spots are brown, slightly sunken and star-shaped. The branches are covered with dark brown mold, and the young fruit bends in the direction of the diseased spot.
There are two main points that farmers should pay attention to in preventing scab: First, they should pay attention to the disinfection of seeds and scaffolds. The scab pathogen will adhere to stems, leaves, tendrils, or remain on scaffolds, but it will become the source of infection by adhering to seeds. Therefore, in the control method, it is necessary to disinfect the seeds and soak them in warm soup at 55℃ 15 minutes. Before 10 planting, the shed should be disinfected. Sawdust and sulfur powder can be mixed and ignited in a fumigation shed for sterilization. Secondly, when farmers encounter this disease, they can use drugs to prevent it, with 600 times of 50% carbendazim wettable powder, 600 times of 75% chlorothalonil wettable powder, 3000 times of 10% world high water dispersant, 6000-8000 times of 40% Fuxing EC and 800 times of 50% chlorpheniramine wettable powder.
4. Moderator: The scab you just mentioned mainly harms leaves and fruits, and cucumber roots are also prone to some diseases. Teacher Jiang introduced us.
Expert: In recent two years, the phenomenon of cucumber seedling death is serious, and the main diseases are Fusarium wilt, Fusarium wilt and root rot, especially in the greenhouse where cucumber is planted in a single year. Bacteria accumulate in the soil and are very prone to disease. In the past two years, it has also been found that grafting cucumber seedlings with diseases is equally serious. According to the research, due to the bacteria in the soil, without protecting the marriage interface, the soil bacteria invaded the unhealed wound, coupled with the injury of Fusarium oxysporum, which led to the longitudinal cracking and atrophy of melon vines. The death of seedlings after onset is caused by vascular bundle necrosis and water and fertilizer can not be transmitted.
Fusarium wilt control measures: (1) Comprehensive treatment of sick and disabled people. Remove the leaves and seedlings with germs in the shed and concentrate them outside the shed to burn them together, so that the whole shed area is free of germs.
(2) Disinfection of the shed. 2 ~ 3 kg sulfur powder and 0.25 kg 8% dichlorvos emulsifiable concentrate are used per mu, mixed with sawdust, lit in piles, sealed for one day and night, dried and odorless before planting.
(3) seed treatment. Pay attention to the temperature tolerance and water content of seeds to ensure the germination rate.
(4) Raising seedlings. Use soil that has never been planted with melons. Spray 50% carbendazim (8 grams per square meter) on the soil. Spraying 2% amino oligosaccharide (Haopu) 500 ~ 800 times before the onset of seedling to prevent damping-off and Fusarium wilt.
(5) Colonization. Apply 4 kg of 50% carbendazim wettable powder at the planting site and mix the soil evenly.
(6) coating the interface for protection. It can be mixed with thiophanate methyl into paste (50 times) and smeared on the interface.
(7) Preventive medication after colonization. 2.8% lethal 1500 times solution, 50% carbendazim wettable powder 500 times solution, and biochemical fulvic acid irrigation; After colonization, cytokinin was sprayed 500 ~ 600 times. Adding 0.2% potassium dihydrogen phosphate and spraying it for 3 ~ 4 times can improve the disease resistance of plants. At the beginning of the disease, the roots were irrigated with 300 times of 3.2% methoxychlor, 350 times of 60% DTM wettable powder and 0/000 times of 20% methyl phosphorus EC/KLOC, and each plant was irrigated with 0.5 kg of liquid medicine. Once every 3 ~ 4 days, continuous irrigation for 2 ~ 3 times.
Control method of stem blight: (1) control: add 60 kg of water to "9281"100 ml and spray plant base.
(2) Treatment: spray "9281"100 ml, 10% Segao 1500 times with 30 kg of water, or smear the diseased stem with hymexazol (50 times). 15% hymexazol 450 times solution. Fungicides also treat Fusarium wilt and root rot.
5. Moderator: How to control cucumber root-knot nematode disease?
Expert: Vegetable root diseases caused by root-knot nematode infection. In recent years, vegetables in China, especially vegetables in protected areas, have been seriously harmed because of continuous cropping and suitable small environment in greenhouses, and their scope is expanding rapidly.
Vegetable root-knot nematodes not only harm cucumbers, but also occur on tomatoes, celery, eggplant, lettuce, cabbage and other vegetables. This disease is common in tomatoes and cucumbers mainly grown in Hebei province. Because nematodes are in the roots and are not easy to be found, it is often noticed that the whole shed is reduced or destroyed.
The diagnosis of root-knot nematodiasis should be based on the above-ground symptoms. If it is found that the plants are not growing well, the leaves in the continuous cropping shed are yellow, wilting and dead, and the results are few and small, the plants should be pulled out to observe the roots. After the root was killed, a series of nodules appeared, and there were white soft objects in the tumors, which should be nematodiasis.
Nematodes can survive in soil for 3 years, and it is not easy to rotate them. It is necessary to start prevention and control from seedling raising. The main methods are as follows:
(1) Select disease-free soil in the field to raise seedlings.
(2) In summer and leisure season, the seriously ill shed should be irrigated, covered with old shed film and closed for 15 ~ 20 days, so that the soil temperature can be raised above 40℃, which can kill nematodes in the soil.
(3) Treatment of diseased plants. Burn all the plants in the sick shed after harvesting, and don't make fertilizer.
(4) Control with chemicals. Using low toxicity, high efficiency and environmental protection pesticide, 10% Fuqiduo granule, 65438+ 0.5 ~ 2 kg per mu, ditching 20cm, planting it in mixed soil immediately after application (evenly), can effectively prevent nematodes from invading or killing them, and the validity period can reach 4 months, that is, a growing season. In addition, in the growing period of vegetables, 65,438+0.8% iverdin EC 65,438+0,000 ~ 65,438+0.500 times of 500 times of Jiakefeng solution was used to irrigate roots continuously for 2 ~ 3 times, with an interval of 7 days, which also had certain control effect.
6. Moderator: Just now, Mr. Jiang introduced to us the diseases that are easy to get during the whole growth period of cucumber and the prevention and control methods. In fact, there are many physiological diseases in the process of cucumber planting. Please tell us again.
Expert: flower topping, also known as melon topping, is the most prone physiological disease. The symptoms are that the upper stem nodes are obviously shortened, the veins are clustered, and there are several flowers at the growing point. There are several flowers in the axils of the lower leaves. The leaves are dark green, rolled down and uneven.
There are several reasons for flower topping: 1, plant root system is damaged. 2. High temperature and drought in the fruiting period. 3. The concentration of drugs such as Fuxing and Heixingdan is too high. 4. Malnourished flower topping is caused by low temperature. When the temperature is lower than 10℃ at night, the assimilated substances formed in cucumber during the day can not be completely transported to the required parts, resulting in dark green and uneven leaves. However, the reproductive growth is too vigorous, forming a large number of female flowers, the top growth is blocked, and there is physiological imbalance. The suitable normal temperature is: in the first half of the night 15℃, and in the morning 10℃ or above. When the temperature in the shed drops to 20℃ during the day, close the curtains in time to keep warm.
Prevention and treatment of flower topping: (1) Flower topping is a typical unbalanced disease. Because the temperature difference between day and night is small, especially at night, raising the temperature is the fundamental measure to prevent the flower from topping. Adjust the temperature of cucumber shed at night to 10℃ ~ 15℃. (2) When topping has occurred, ripe melons should be removed in time, and redundant female flowers should be removed. Spraying 6000 times brassinolide, or 1% brown sugar water and 1000 times urea to balance nutrition and reproductive growth, and adjust the newly opened female flower to the normal position 40 ~ 50 cm away from the growth point.
7. Moderator: Teacher Jiang, how to deal with fertilizer damage and element deficiency caused by improper fertilization and watering during cucumber planting?
Expert: Fertilizer damage and nutrient deficiency diseases are physiological diseases of cucumber caused by improper fertilization and watering, mainly including Phnom Penh leaves, parachute leaves, ammonia damage, deformed melons and bitter melons.
(1) Phnom Penh leaf, parachute leaf. Due to the high concentration of excessive fertilization and soil solution, salt accumulated in leaves, which led to the formation of Phnom Penh leaves. In addition, it is because plants lack calcium, but the root cause of calcium deficiency is the chilling injury of roots.
(2) ammonia damage. Before planting melon seedlings, apply incompletely decomposed chicken manure, which will discharge a lot of ammonia in the closed greenhouse, which is the most likely to cause ammonia damage to melon seedlings. In addition, due to poor ventilation in winter, if the available nitrogen fertilizer is applied without covering or covering the soil, ammonia damage will occur due to its volatility. When ammonia damage occurs, the leaves should be watered, aired and sprayed with vinegar in time.
(3) Element deficiency. Lack of elements can lead to different symptoms, such as iron deficiency forming yellow-edged leaves and yellowing leaves; Zinc deficiency causes the upper leaves to turn yellow; Lower leaves lacking magnesium turn yellow; Calcium-deficient Phnom Penh leaves and parachute leaves; The lower part of manganese deficiency is like a parachute; The upper leaves lacking boron are dark green, thickened and curled. Defensive measures: according to the symptoms, diagnose in time, suit the remedy to the case, make up for the deficiency, and the suitable concentration of foliar spraying is 0. 1 ~ 0.3%. It is also necessary to scientifically apply fertilizers, mainly straw fertilizers, decomposed livestock manure and other organic fertilizers, fully apply base fertilizers and adjust chemical fertilizers.
(4) deformed melons. Cucumber malformed melons are mainly characterized by thin waist melons, big belly and sharp mouth melons, curved melons and so on.
Defensive measures: adjust the temperature, humidity, light and moisture in the protected area to meet the needs of cucumber growth and development. Apply formula fertilization technology and then apply organic fertilizer. Check the female flower in time after sitting on the melon, remove the deformed melon, reduce nutrient consumption, and hang the bent melon straight with a small weight.
8. Moderator: Teacher Jiang, at the end of the program, what else should we pay attention to when planting cucumbers?
Expert: At present, many cucumbers taste bitter. These bitter and bitter cucumbers have the same appearance as normal commercial cucumbers, but they taste salty and bitter when eaten raw. The bitterness of flower heads and pedicels is stronger than that of the middle part, and there is no difference when cooked. The reason is that too much nitrogen and insufficient water form momordicin at low temperature, which leads to bitter taste of melon strips. In this case, you can spray a regulating liquid such as 6000 times more love and 300 times brown sugar.
In the process of planting, we should also pay attention to the abnormal position of melons. When the plant grows normally, the flowering pitch is about 40 ~ 50 cm from the top of the melon vine, and the faucet is "bud-shaped". If the flowering node position is lower than or greater than this standard, it means that the faucet grows abnormally. Mainly manifested in:
(1) The flowering node position is low. If the flowering node is more than 50 cm away from the top of the melon vine, it is a sign of overgrowth of plants. Sufficient fertilizer and water, high night temperature and insufficient light are easy to form this plant type.
(2) The flowering node rises to the top. The flowering pitch is less than 40 cm from the top of melon vine, which is a sign of weak plant growth. This plant shape is particularly easy to appear when the growing point "blooms". In most cases, the flowering pitch is 20 ~ 30 cm from the growing point. But in severe cases, the flowering node will reach the top of the melon vine, which is the result of extremely weak vegetative growth and excessive reproductive growth. This situation is easy to happen when the root system of cucumber is extremely fragile or seriously damaged. Water, fertilizer, temperature and pruning should be managed in a targeted manner. Foliage can be sprayed with 6000 times of brassinolide and foliar fertilizer, and adjusted twice every 7 days 1 time.