Occurrence and control techniques of common physiological diseases of greenhouse cucumber
According to the investigation, in recent years, the physiological diseases of cucumber in greenhouse have increased year by year, such as needle-nosed melon, bitter melon, physiological wilt disease, low-temperature physiological disease, leaf burning disease, etc., the majority of vegetable farmers have a headache during the cultivation process. It seriously affects the yield and quality of cucumber. Therefore, it is necessary to identify and control the physiological diseases of cucumber in time. The main types of physiological diseases of cucumbers in protected areas are as follows:
Sharp-billed melon
1. Symptoms The melons do not grow into commercial melons. The tops of the melons stop growing and form a thin tip.
Causes Insufficient illumination in the northern part of the greenhouse, small temperature difference between day and night, excessive density, poor light transmission, insufficient supply of fertilizer and water when the melons are inflated; weak plants, small leaves, yellow leaves, growth points are inhibited, roots are damaged; late growth of plants It is aging, or is harmed by pests and diseases, or it is rainy and rainy; a leaf section grows a lot of melons, and it is prone to grow a pointed melon.
2, prevention and control methods to strengthen water and fertilizer management, increase the application of organic fertilizers, and apply organic fertilizers such as (cattle, horse manure) and other hot fertilizers, improve soil water supply, fertilizer supply capacity, prevent plant premature aging; rationally build warm sheds, increase light transmission Degree; reasonable close planting; do a good job in the prevention and control of pests and diseases to prevent plants from suffering pests and diseases.
Leaf burn
1. Symptoms generally occur in the middle and upper leaves of the plant. Small white patches appear on the leaf surface, and the shape is irregular or polygonal. When enlarged, it is white plaque, and the light only leaves are burnt, and the weight is half. Burning above and below the leaves. Causes When the relative humidity in the shed is less than 80%, when there is a high temperature of about 40 °C, it will cause high temperature damage. If there is no air at noon, or the amount of air is not enough, or the high temperature suffocation time is prone to leaf burn.
2, prevention and treatment methods First, strengthen the management of the shed, if the shed temperature exceeds 35 °C, it should be immediately ventilated and cooled. It is also possible to use grass to remove shading and cool down. Secondly, it is necessary to strictly control the time and temperature of the shack when controlling the downy mildew in the high temperature shack. If the soil moisture is small, it can be watered one day before the shack, and the cucumber leaves can be avoided. The occurrence of burning disease.
Bitter melon
1. Symptoms The excessive accumulation of bitterin in cucumber causes the melon to taste bitter and cannot be eaten. The cause of excessive nitrogen fertilizer, phosphorus, potassium fertilizer is insufficient, especially the one-time application of nitrogen fertilizer is too much, prone to bitter melon; the absorption of nitrogen, phosphorus and potassium by cucumber basically follows the ratio of 5:2:6, otherwise there will be birth imbalance. Caused by long, or the fruit is not uniform, bitter melon is easy to appear on the side branches; the temperature is too high, above 32 °C, causing assimilation ability, excessive loss, malnutrition; soil is too dry; cloudy days, less sunshine, The ground temperature is low, the water nutrient absorption is suppressed, and it is easy to form bitter melon; it has a certain relationship with the variety.
2, prevention and treatment methods formula fertilization, so that nitrogen, phosphorus, potassium fertilizer rational mix; advocate the application of organic farmyard manure and biogas fertilizer. Watering in time to prevent drought; control temperature, avoid high temperature and low temperature; use varieties that are not easy to produce bitter melon.
Flower topping and melon
1. Symptoms of flower topping show that the growth point of cucumber becomes the organ of flower, and the melon strip stops growing after flowering. In addition, low temperature and high temperature impede fertilization and produce melons.
The disease usually occurs in the early stage of the result. The high temperature and drought in the shed, especially when the soil is dry, the fertilizer is too much, or the soil is wet, the roots are prone to occur, which leads to the weakening of root absorption. All these reasons will lead to the emergence of flowers in the cucumber. Or melon.
2, the prevention method uses loose soil, pay attention to the management of water and fertilizer temperature, properly control the temperature, to achieve moderate temperature and humidity during the day, temperature control is controlled at 25 ° C ~ 30 ° C, night 15 ° C; reasonable close planting; cloudy low temperature It can be used for foliar spray fertilizer; suitable ventilation can be used for carbon dioxide fertilization; promote the accumulation of assimilated materials, strengthen fertilizer management and pest control.
Physiological wilting
1, the symptoms of the whole plant leaves wilting, and some can recover sooner or later, died a few days later, no lesions in the stem.
In the early stage of collecting melon, the toxic water produced in the soil caused the toxic gas in the soil, causing the root system to develop poorly. It appeared wilting at noon on sunny days and recovered at night. After a few days, the plants no longer recovered and died. In the hot season, it turned bright after a sudden rain. The high temperature and high humidity in the shed caused the transpiration of the leaves to be blocked, causing wilting and even death.
2, prevention and treatment methods to avoid water accumulation in the greenhouse, try to use greenhouse irrigation technology; strengthen the management of the cultivator, increase the greenhouse watering under sunny and high temperature conditions. If the living soil layer is too deep, it is necessary to level the surface after watering to make the soil deep, transparent, fine, flat and solid, and maintain good permeability of the soil.
Low temperature physiological disease
1. The symptoms are low temperature, and the leaves are yellowish white. If the duration is long, the plants do not show roots or the flower buds do not differentiate. The light and heavy leaves have water stains, spots, shrinkage, curling, wilting, and even death. The cause of cucumber is weak in cold tolerance, and plants at 0 to 10 °C will suffer. When the temperature is lowered to 3 to 5 °C, the physiological function is impeded and damage is caused. The cells cause dehydration or cause the cells to rise and die, and the plants die and die.
2, prevention and treatment methods use low temperature resistant varieties; strengthen insulation measures, seedlings can be covered with plastic film; double-layer straw curtains on the shed; smoke or temporary warming; consciously start low temperature exercise before planting, intermittently reduce The temperature of the seedbed can be carried out for 5 to 7 days, 0.5 to 1 hour each time. You can also spray some 500ppm streptomycin to prevent this disease.
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