Prevention and control of common diseases of cucumber?
1. Symptoms The disease can occur in the whole growth period of cucumber, mainly damaging leaves. At the beginning of the disease, there are small yellow spots on the back of the leaves. With the development of the disease, the spots gradually expand and are limited by the veins, forming polygonal yellow spots. When the disease is serious, the small spots merge into large spots, and under wet conditions, a gray-black mold layer grows on the back of the spots. The diseased leaves develop from bottom to top, and in severe cases, the whole leaves die.
2. Transmission route and onset conditions The disease is a disease infected by downy mildew, which is mainly transmitted by airflow and rain. Sporangium germinates directly, produces bud tube, invades the host through stomata or directly penetrates the epidermis. The transmission route is mainly from greenhouse cucumber to field cucumber, then from field to summer and autumn cucumber, and then to greenhouse cucumber. High humidity is an important condition for cucumber downy mildew. Sporocysts produced by pathogenic bacteria need a relative temperature of more than 83%, and the germination and invasion of sporocysts need water droplets or water films. The sporangium on the leaf surface can't germinate and die in 2 ~ 3 days, so the water drop or frog on the leaf surface is the decisive factor of downy mildew. If the ventilation is poor, the humidity is too high, the temperature adjustment is not good, and the temperature difference between day and night is large, it is easy to cause water droplets or water films on the leaves, which is conducive to the germination and invasion of germs. The temperature range of pathogen invasion is 10 ~ 25℃, and the optimum temperature is 15 ~ 22℃. When the temperature is higher than 30℃, it is not suitable to get sick. The higher the temperature, the greater the inhibitory effect on pathogenic bacteria. In the presence of water, temperature is the main factor causing disease in the morning and evening.
3. Select new disease-resistant varieties as control methods. Such as Jin Yan No.4, Jinchun No.2, Jinza No.2 ~ 4, Changchun Milla, Shandong Milla, etc. Strengthen the management of planting and yield increase, adopt the cultivation technology of high ridge plastic film mulching, water under the film, and reduce the number of watering. Strengthen ventilation and reduce air humidity. Increase the application of phosphorus and potassium fertilizer to improve the disease resistance of plants. Remove the old yellow leaves at the lower part in time after fruiting. Spraying 0.2% potassium dihydrogen phosphate outside the roots or spraying1:1:kloc-0/00 mixed solution of urea and sugar can increase the total sugar content of functional leaves and improve their physiological disease resistance. High temperature stuffy shed. Choose a sunny morning, close the doors and windows of the greenhouse, so that the temperature in the greenhouse can be raised to 45℃, and the maximum can not exceed 48℃. After 2 hours of proper ventilation, the wind will gradually reduce the temperature in the greenhouse and return to normal temperature. You must water the shed the day before it closes. If the plant is higher, the growing point can be lowered downward.
Chemical control. The following drugs can be selected at the initial stage of the disease:
① 800 ~ 1000 times of 25% poisonous mildew wettable powder.
②90% Yishuangling wettable powder is 500 ~ 600 times.
③75% chlorothalonil wettable powder is 500 ~ 600 times.
④72% Kelv wettable powder is 600 ~ 800 times.
⑤72% acupuncture water solution 600 ~ 1000 times.
⑥45% chlorothalonil fumigant, 250g per mu each time.
⑦5% chlorothalonil or 5% wanmeiling powder, per mu 1 kg, once every 7 ~ 10 days, 3 ~ 5 times in a row.
Second, cucumber powdery mildew
1, symptom diseases mainly harm leaves. At the early stage of the disease, white round powdery spots are produced on the back and leaves, which expand into sheets and grow a layer of white powder, gradually turn gray, and the leaves turn yellow and dry and die.
2. Transmission route and onset conditions The disease is a fungal disease caused by powdery mildew of Powdery Mildew Family, which can occur in protected cultivation areas all year round. Spread by airflow or rain, from greenhouse to field, and then to greenhouse. The occurrence of powdery mildew is closely related to temperature, humidity and cultivation management. The optimum temperature of powdery mildew is 20 ~ 25℃. When the temperature exceeds 30℃ or is lower than 10℃, the pathogen is inhibited. Powdery mildew has a wide adaptability to humidity. The higher the humidity, the better the spore germination, but when the relative humidity is lower than 25%, the pathogen can still germinate. In cultivation management, the disease is prone to occur in plots with too high density, too much nitrogen fertilizer, poor ventilation and light transmission, insufficient soil moisture or excessive irrigation and humidity.
3. Selecting disease-resistant varieties as control methods. Such as Hero 1, Jin Fu Heat Resistant King, Gold Award Zhengyang, Taishan Heat Resistant Supreme Treasure, Dongfang Longji Green Cucumber, Xiasheng Jieduo, Kangqing Black Green No.3 and other excellent cucumber varieties. Protected areas need fumigation and disinfection, and they should be disinfected with sulfur powder or chlorothalonil smoke agent before planting. The method of sulfur powder fumigation is to use 0. 13 kg of sulfur powder and 0.25 kg of sawdust every 55 cubic meters. If you use 250 grams of chlorothalonil smoke agent per mu every time, put it at night, light it and seal it overnight, and open the doors and windows for ventilation the next morning.
Strengthen the management of fertilizer and water, pay attention to ventilation and light transmission in the shed, and prevent plants from white growth and premature aging. Chemical control.
40% Fuxing EC 8000 ~ 10000 times, 25% fenxiuning wettable powder 1500 times, nongkang 120 biological agent 120 ppm, or 50% carbendazim wettable powder 600 ~ 800 times, which can be used alternately.
Three, cucumber bacterial angular leaf spot
1, symptoms The disease mainly harms leaves, but sometimes it also harms stems and melons. Cotyledons are damaged, initially waterlogged, round or oval concave spots, and then turned into yellow-brown spots and dried up. When the leaves are initially damaged, they will produce pinhead-sized water stains, then turn light brown and become polygonal due to the veins. When the humidity is high, tremella pus is produced on the spots on the back of leaves, which is a white transparent film after drying. In the late stage of the disease, it is fragile and easy to crack and perforate. The diseased spots on stems and fruits are soaked in water, nearly round, and then turn light gray. Cracks often appear in the middle of the lesion. When wet, bacterial pus is produced on the diseased spot, which invades the pulp, making the pulp discolored, rotten and smelly. Young melons often rot and fall early after being killed.
2. Transmission route and onset conditions The disease is a bacterial disease. It is mainly spread by airflow, irrigation water, rain, insects and farming. , and invade from pores, water holes, wounds, etc. High temperature and high humidity are important conditions for bacterial angular leaf spot. The onset temperature ranges from 20℃ to 30℃, and the optimum temperature is about 25℃. The daily average temperature is below 12℃, and the disease is serious when the humidity is high. High planting density, insufficient phosphorus and potassium fertilizer, poor ventilation, low temperature and high humidity, serious diseases in continuous cropping plots, and serious diseases in low temperature and rainy years.
3. The control method is to disinfect the seeds of disease-resistant varieties. Seeds were soaked in warm water at 55℃ 15 minutes, or soaked in 500 times solution of 50% mancozeb10.5 hours, or soaked in 40% formaldehyde 150 times solution10.5 hours, and then washed with clear water to accelerate germination.
Strengthen cultivation management. The seriously ill plots shall be rotated for more than two years, ventilated in time to reduce humidity, and the accumulated water in the fields shall be eliminated. The sick and disabled bodies shall be removed in time after harvesting and destroyed centrally.
Chemical control. Spraying 50%DT800 times solution or 70% kocide wettable powder 400 times solution or neophytomycin 5000 times solution or Bordeaux solution 1: 2: 300-400 times solution or 80% Ludebao wettable powder 500 times solution1time every 7-65438 days for continuous control for 3-3 days.
Four, cucumber gray mold
1. Symptoms The disease mainly harms the flowers and young melons of cucumber, and sometimes also harms the leaves and stems. Most pathogens begin to infect flowers. After the flowers are killed, a grayish-brown mold layer grows, which infects young melons and causes umbilical rot. At first, the waterlogging of young melons faded, and the diseased parts gradually became soft and rotten, with a dense gray-brown mold layer on the surface. Ill flowers and fruits fall on stems and leaves, leading to leaf diseases. Leaf diseased spots are waterlogged, then light brown, wheel-shaped, with obvious edges, and sometimes brown mold layer is produced in the middle of diseased spots. The stem is killed, causing the diseased part to rot, which can lead to the death of the whole plant in severe cases.
2. Transmission route and onset conditions The disease is a fungal disease infected by Botrytis cinerea. Pathogens mainly overwinter in sick and disabled people and soil, becoming the primary source of infection, and re-infection is formed through airflow, water splashing and agricultural operations. Ill flowers and fruits will cause re-transmission. The air temperature is about 20℃, insufficient illumination on cloudy days, high humidity in protected land, untimely ventilation, relative humidity above 90% and long dewing time are important conditions for the spread of gray mold. If the temperature is higher than 30℃ and the relative humidity is lower than 90%, the disease will stop spreading.
3. Prevention and control methods Strengthen cultivation management, enhance illumination, strengthen ventilation, water under the film, avoid watering on cloudy days, and prevent excessive humidity. Clean the garden, remove the diseased flowers, melons and leaves in time and take them out of the site for centralized destruction. Chemical control. At the initial stage of the disease, you can choose 10% sukeling smoke agent or 45% chlorothalonil smoke agent, 250g per mu each time, and smoke for 3 ~ 4 hours. Dust agent, 5% chlorothalonil dust remover or 6.5% metalaxyl dust remover can also be sprayed in the evening, each time per mu 1 kg. You can also use 50% prochloraz WP 2000 times solution, 50% chlorpheniramine WP 1500 times solution and 75% chlorothalonil WP 600 times solution. Take the medicine once every 6 ~ 7 days, and control it for 3 ~ 4 times continuously. The medicine is required to be sprayed on flowers and young melons. Adding 0. 1% of 50% zineb wettable powder or 50% chlorpheniramine wettable powder to dip or spray flowers at the initial flowering stage has obvious effect.
Verb (abbreviation of verb) cucumber Fusarium wilt
1. Symptoms mainly harm the roots and stems of cucumber. When the seedling is sick, the stem base turns yellow and brown, the cotyledons wither and droop, and the roots rot. The adult stage generally starts from the initial stage of fruiting, and the diseased plants wilt and droop gradually from bottom to top, like water shortage. A few days later, the stem base of the diseased plant contracted and amber colloidal liquid flowed out. Under wet conditions, a pink or white mold layer will grow on the stem base, and the vascular bundle will turn brown after the stem base is cut, which is an important feature of Fusarium wilt. With the development of the disease, the diseased plant dies quickly, and the base of the stem is easy to split into hemp fibers longitudinally, which is easy to pull up.
2. Transmission route and onset conditions The disease is a fungal disease infected by Fusarium. Bacteria overwinter in residues and soil and become the primary source of infection in the coming year. Seeds can spread far, and soil, fertilizer, irrigation water, insects and farm tools can spread diseases. Bacteria have strong vitality and can survive in soil for more than 5 ~ 6 years. Therefore, the number of pathogenic bacteria in soil is the decisive factor of the occurrence degree of diseases and the main source of infection of diseases. Plots with continuous cropping, high soil moisture and waterlogged roots are easy to promote the occurrence and spread of Fusarium wilt. High temperature and high humidity are favorable conditions for Fusarium wilt. When the temperature is 24 ~ 27℃ and the soil temperature is 25 ~ 30℃, the disease will occur quickly. Excessive nitrogen fertilizer aggravated the condition of acid soil (pH = 4.6 ~ 6.0). The plots with more nematodes and flooded plots are more serious.
3. Select new disease-resistant varieties as control methods.
Rotation with non-melon vegetables, leeks and other crops to reduce the accumulation of germs in the soil. Adopting the cultivation techniques of high ridge cultivation and watering under plastic film, timely eliminating the accumulated water in the field, strengthening ventilation and light transmission, increasing the application of phosphorus and potassium fertilizer, and improving the disease resistance of crops.
Grafting to prevent disease, grafting cucumber with sunspot pumpkin with developed root system, low temperature tolerance and Fusarium wilt resistance, the control effect can reach above 95%, which is an ideal method to control cucumber Fusarium wilt at present.
Disinfect in summer in sunlight: cut1000kg of straw into 4-6cm long per mu, spread it evenly on the ground, then spread100kg of lime evenly, dig the ground to a depth of more than 25cm, cover it with plastic film, pour enough water, and then seal the greenhouse or greenhouse 15-20 days, and the local surface soil temperature will reach 60.
Chemical control.
Spraying 50% carbendazim wettable powder 500 times or 70% thiophanate-methyl wettable powder 800 times at the initial stage of the disease. Or irrigate the roots with 70% Dixon wettable powder solution of 1000 times or 50% Likujing solution of 800 times, 250 ml per plant, every 7 days 1 time, 3 times in a row.
Six, cucumber scab
1. Symptoms Cucumber will get sick during the whole growth period, and leaves, stems and melons will be hurt. The diseased cotyledons of the seedlings were yellow-white, nearly round, and the seedlings stopped growing. In severe cases, the heart leaves withered and the whole plant died. Leaf disease, initially wet circular spots, with a diameter of 65438 0 ~ 2 mm, is yellowish, and the spots are prone to star-shaped cracking and perforation after the disease. Petiole, vine and stalk are damaged, and there are long spindle lesions with cracks and subsidence in the middle. White secretion can be seen in the affected area, and then it turns into amber colloid. When wet, the affected area will grow a gray-black mold layer. When the melon sticks were killed, dark green round to oval lesions appeared at first, with glue overflowing, and later turned amber. The focus was 2 ~ 4 mm in diameter, and pits and cracks were scabbed. The diseased tissue stopped growing, resulting in abnormal melon strips. When the temperature is high, you can see the gray mold layer in the sky, and the melon strips are generally not rotten. The main difference between cucumber scab and bacterial angular leaf spot is that the diseased spot on the leaves of bacterial angular leaf spot is polygonal, limited by veins, the veins are not damaged, the diseased leaves are not twisted, the diseased spots are perforated in the later stage instead of star-shaped cracking, the pus overflowing from the injured melon sticks remains amber, and the diseased melons are wet and rotten.
2. Transmission route and onset conditions The disease is a fungal disease infected by Cladosporium cucurbitae. The pathogen overwinters on the diseased body, soil or its vicinity, scaffolds and seeds, directly penetrates the epidermis of leaves, melons, stems and vines, or invades from wounds or stomata. Pathogens can grow in the temperature range of 5 ~ 30℃, and the optimum temperature is 20℃. The continuous cropping time in protected land is long, the planting density is too high, the plants are too long, the ventilation and light transmission are not timely, and even it rains more heavily for a long time.
3. Prevention and control methods Seed quarantine is the main way to prevent seed-borne diseases. Implement production quarantine to produce disease-free seeds in the field. Chemical control. At the initial stage of the disease, 40% Fuxing EC 8000 times solution or 75% chlorothalonil wettable powder 600 times solution, or 50% chlorpheniramine wettable powder 1500 times solution can be selected for spraying, or 45% chlorothalonil smoke agent is 250g per mu each time. Spraying should be even and thoughtful, and the young parts and growing points should be sprayed once every 5 ~ 7 days, and the spraying should be continuously controlled for 3 ~ 4 times.
Seven, cucumber Fusarium wilt
1. Symptoms The disease mainly harms stem base, leaves and fruits. Most of the seedlings infected from tender shoots, wilted and rotted at first, such as dark green water stains, the diseased parts obviously shrank, and the leaves above the diseased parts gradually withered, resulting in dry and bald shoots. Leaf diseases, there are round dark green waterlogging spots, wet spots quickly expand into large spots, the edge is not obvious, and the whole leaves rot. In the adult stage, diseases mostly occur in young branches and the base of lateral branches. The diseased part is dark green with water stains, obviously shriveled and rotted, the stems and leaves above the diseased part die, and the vascular bundle of the diseased stem does not change color. The melon strips are damaged, resulting in dark green water stains and nearly round pits. When the humidity is high, the disease develops rapidly, the melon strips shrink and a sparse gray-white mold layer grows in the later stage. The difference between cucumber Fusarium wilt and Fusarium wilt. The vascular bundle at the base of the stem of the epidemic disease does not change color, and a sparse gray-white mold layer grows in the later stage of the disease, instead of a white or pink mold layer.
2. Transmission route and onset conditions The disease is a fungal disease infected by Phytophthora cucumber. Germs overwinter in diseased bodies and soil. Seeds, garbage and fertilizers can carry germs and spread diseases through irrigation water, airflow and wind and rain. The occurrence and prevalence of epidemic diseases are closely related to microclimate. High temperature and high humidity are beneficial to the occurrence and development of pathogens. The onset temperature is 5 ~ 37℃, and the suitable temperature is 28 ~ 32℃. In a suitable temperature range, continuous cropping, rainy days, excessive watering, high humidity, poor drainage, sticky soil and incomplete application of organic fertilizer may all cause the disease.
3. The control method is rotation with non-melon crops.
Adopt high ridge cultivation, cover the ridge with plastic film or wheat straw, use underground irrigation under the film to drain the field moisture in time, make good ventilation and light transmission, and reduce the humidity in the field.
After harvesting, remove the diseased leaves from the field and destroy them in time.
Seed disinfection. You can choose 40% formaldehyde 100 times solution to soak the seeds for 30 minutes, take them out, wash them and dry them for later use. Or seed dressing with 25% Ruifu wettable powder which is 0.3 times of the seed weight, or soaking the seed with 600-800 times of liquid for 30 minutes, and then accelerating germination for later use.
Chemical control: at the initial stage of onset, 64% antiviral alum M8 wettable powder, 700-800% Yishuangling wettable powder or 600% chlorothalonil wettable powder can be sprayed, or 25% metalaxyl wettable powder and 40% thiram wettable powder can be sprayed.
Eight, cucumber anthracnose
1. Symptoms Cucumber can get sick during the whole growth period. At the seedling stage, the cotyledon edge appeared semi-circular lesions and slightly depressed. In the adult stage, the leaf lesions are nearly round and vary in size. At first, they were soaked in water, and soon dried up, turning reddish brown with yellow halo on the edge. There are often several small lesions connected into irregular large spots, and black spots are formed on the lesions. When wet, the lesion produces a pink sticky substance. When dry, the lesions often crack and perforate. The diseased spots on stems and petioles are oval or spindle-shaped, dark brown and slightly concave. The diseased spots on the melon strips are round and brown, slightly sunken and cracked in the middle, and pink mucilage is produced on the diseased spots in the later stage.
2. Transmission route and onset conditions: the disease is infected by Colletotrichum fungi, and the pathogen overwinters on the surface of seeds, diseased bodies and soil with hyphae and sclerotia, which will become the primary source of infection in the coming year. Under appropriate conditions, the invasion of the host will lead to diseases. High temperature and high humidity are the main conditions of the disease. The relative humidity is 87% ~ 95%, and the optimum temperature is 24℃. When the humidity is less than 54%, the disease does not occur, and when the temperature is higher than 28℃, the disease is mild. Poor ventilation and light transmission, excessive watering, continuous cropping, excessive nitrogen fertilizer and plant growth in protected areas are all conducive to the occurrence of diseases. 3. The control method is to select disease-free seeds or collect seeds from disease-free plants.
Strengthen cultivation management, timely ventilation and light transmission, prohibit flooding, clear the accumulated water in the field in time after rain, reduce the humidity in the field, and control the humidity below 70%. Apply more phosphorus and potassium fertilizer, implement crop rotation, remove diseased leaves and melons in time after discovering diseased plants, and use drugs to prevent and control them in time.
Chemical control: 500 times of 50% carbendazim wettable powder, or 500 times of 75% chlorothalonil wettable powder, or 300-400 times of 50% anthrax thiram wettable powder, or 45% chlorothalonil smoke agent can be used at the initial stage of the disease, 250g/mu each time. Take the medicine once every 7 ~ 10 day, and take the medicine for 3 ~ 4 times continuously.
Nine, cucumber Sclerotinia sclerotiorum
1. Symptoms mainly harm stems and fruits, mostly occurring on branches at the base and main side of stems. At first, light green waterlogging spots were produced, which were light brown after expansion. There were white hyphae on the surface of the diseased area, black sclerotia in the stem, and branches and leaves above the diseased area withered and died. Fruit diseases are mostly caused by melon diseases, which are soaked in water at first, and the surface is covered with white hyphae and black sclerotia. Leaf diseases are gray to light brown, with round lesions, inconspicuous edges, wet rot and sparse mold layer. At seedling stage, water spots appeared at the base of diseased tender stems, which quickly wound around the stems, leading to the collapse of seedlings.
2. Transmission route and onset conditions The disease is a fungal disease infected by Sclerotinia sclerotiorum. Pathogens overwinter in seeds and soil and produce ascospores under suitable conditions. Spores spread with airflow, and diseased flowers with bacteria can cause reinfection. Low temperature and high humidity are conducive to the occurrence and prevalence of diseases. The temperature is 13 ~ 20℃, and the suitable relative humidity is 98% ~ 100%. The optimum temperature for sclerotia germination is about 65438 05℃, and it can die within 5 minutes if it exceeds 50℃. The protected land has long continuous cropping time, the outdoor air is not timely, and the plots with high humidity are seriously ill. Early ventilation, large ventilation, low humidity and sufficient sunlight are all light.
3. Prevention methods Soil disinfection. In summer, the protected area turned 30 cm deep, and the sclerotia turned under the soil. After irrigation for 10 days, the ascus could not be unearthed.
Seed disinfection. Soak the seeds in warm water at 50℃ 10 minute. Adopt high ridge cultivation, plastic film mulching and irrigation under plastic film. After discovering the strains of central diseases, they should be removed in time and treated with drugs.
Strengthen ventilation and light transmission to prevent low temperature and excessive humidity.
Chemical control. At the initial stage of the disease, 50% Sukeling WP 1500 times, 40% Junhejing WP 1000 times, 50% Nongliling WP 1000 times, 50% chlorpheniramine WP 1000 times or 50% chlorpheniramine WP. Take the medicine once every 10 day for 3 ~ 4 times in a row.
Ten, cucumber stem blight
1. Symptoms The disease mainly harms stems and leaves. When the stem and base are diseased, round or spindle-shaped yellow-brown, oil-soaked, slightly sunken spots, amber colloid and small black spots scattered on the surface are produced. After the onset of leaf disease, large round or irregular lesions appear, and some lesions develop inward from the leaf edge into V-shaped or semi-circular light brown to yellowish brown, and the lesions are easy to break in the later stage, and the lesions are densely covered with black spots. The diameter of leaf lesions is 10 ~ 35 cm, and a few lesions are larger. The diseased leaves are yellow from bottom to top and do not fall off. In severe cases, only the top 1 ~ 2 leaves are left.
The difference between Fusarium wilt and Fusarium wilt: Fusarium wilt mostly develops from the stem surface to the inside, vascular bundles do not change color, and the whole plant will not die, which is an important difference from Fusarium wilt.
2. Transmission route and pathogenic conditions: Fusarium wilt is a fungal disease infected by Coccidium melonis. Bacteria overwinter in the sick and the soil, mainly spread through irrigation water and airflow, and invade from stomata, water holes or wounds. Bacteria carried by seeds can cause cotyledons to get sick. High temperature, high humidity, poor ventilation, weak plant growth and virtual length, and the plots repeatedly planted for many years are easy to cause diseases.
3. The control method is to select disease-free seeds or seeds from disease-free plants. Implement rotation for more than 2 ~ 3 years.
Cultivate strong seedlings, increase the application of phosphorus and potassium fertilizer, enhance the stress resistance of plants, strengthen ventilation and light transmission, reduce temperature and humidity, and improve the field microclimate.
Chemical control.
At the initial stage of the disease, 600 times of 75% chlorothalonil wettable powder, 800 times of 70% thiophanate-methyl wettable powder, 50% carbendazim wettable powder 1500 times, or 45% chlorothalonil smoke agent can be used, 250g per mu each time, or 800 times of 40% Fuxing EC, every 7 ~ 10 days.
XI。 Occurrence and control of cucumber and melon diseases
1. The main symptom is that the newly seated melon buttons or developing small melon strips stop growing, gradually turn yellow and shrink from the tip of the melon, and finally dry up and fall off.
2. The main causes of melon diseases are excessive irrigation when female flowers wither, poor soil permeability, weak root activity, or late picking of big melons, and various organs compete for nutrients, resulting in insufficient nutrient supply and yellowing of young melons. Under the condition of continuous rainfall and insufficient light, the products of photosynthesis are few, and the young melons who just sat down can't get enough nutrition and stop growing. In addition, lack of light, high temperature, less photosynthetic products and more nutrient consumption lead to malnutrition of young melons. In the case of sufficient nitrogen fertilizer, too much water, insufficient light and too fast plant growth, the nutritional growth of young melons can not be fully supplied, which is easy to cause melon melting.
3. Prevention and control methods Strengthen cultivation management, properly control watering, strengthen ventilation, increase light, improve photosynthetic intensity, control temperature and humidity, prevent melon seedlings from growing in vain, pick melons at the right time, and moderately sparse melons.
Twelve, the occurrence and control of cucumber "flower topping"
1. Symptomatic cucumber topping mainly occurs at seedling stage or early planting stage. Its symptoms are that the growing point no longer grows upward, the internodes near the growing point become shorter, the flowering nodes rise, and serious flowers bloom at the top. After flowering, the melon strips no longer elongate and the seedlings stop growing.
2. The causes of the disease are drought, lack of fertilizer, nighttime temperature lower than 15℃, high soil salt concentration, root damage and other factors.
3. Prevention and control methods: strengthen water and temperature management during seedling raising, apply more organic fertilizer, transplant in time, avoid root damage during transplanting, avoid flooding and water accumulation in the field, and maintain good soil permeability. Properly remove female flowers to promote growth. If the fertilizer supply is insufficient, 0.2% ~ 0.3% potassium dihydrogen phosphate aqueous solution can be sprayed.
Thirteen, the occurrence and prevention of deformed melon
1. Symptoms and causes. The main reasons are over-dense planting, too many fruits, or too many leaves, small female flowers, incomplete development, drought damage to the root system, resulting in insufficient nutrition supply.
Thick-tailed melon and thin-tailed melon. Cucumbers planted under the conditions of too many melons, insufficient soil fertilizer and nutrition, drought, or high soil salt concentration are easy to produce thin-tailed melons.
When cucumber is planted under the condition of insufficient potassium, nitrogen and calcium, the occurrence of thick-tailed melon is more. Potash-deficient plots are prone to grow thick-tailed melons. Close planting, insufficient light, many leaves and high temperature are also easy to produce thick-tailed melons.
High temperature and drought, low temperature and low humidity, and lack of potassium, calcium and boron in ammonium are the main factors of Hami melon occurrence.
2. The control method is reasonable and close planting, the lower yellow leaves are removed, the illumination is increased, and the photosynthesis is improved. Prevent flooding, strengthen ventilation and reduce humidity. Increase the application amount of organic fertilizer, and timely supplement potassium fertilizer and boron fertilizer.