The green onion stem tip is a major obstacle to the quality and yield of welsh onion, which often leads to a decline in quality and yield, directly affecting the economic benefits of vegetable farmers. It is important to understand the causes of the sharpness of green onions and take targeted preventive measures. First, the physiological dry tip 1, acidic soil damage caused by dry tip neutral soil suitable for onion growth, when the application of organic fertilizer is less, a large number of application of ammonium sulfate, superphosphate will make the soil acidification, causing onion leaf growth is slow, thin, outer leaves yellow. Control measures: Apply enough decomposed organic fertilizer and apply 150 kg of calcium oxide per acre. 2. Drought does not pay attention to watering during the production process of dried shallots. The soil is dry, and the plants lack of water can easily cause dry tips. Preventive measures: According to the different needs of the different growth stages of onion on water, timely, adequate watering. Appropriate control of water at the seedling stage, undying not pouring; nutrient growth combined with topdressing, soil watering in time to ensure adequate water supply; control watering 10-15 days before harvest. 3, lack of trace elements caused by dry tips calcium deficiency, heart tip yellowing, physiological resistance; lack of magnesium, outer leaves yellowing. Control measures: can be top-dressed, such as 0.1-0.3% calcium nitrate, 0.1% magnesium chloride spray. 4. The growth temperature of dry shallots caused by high temperature or freezing injury is 7-35°C. When the temperature exceeds 35°C, the tips of leaves are dry and below 7°C, the tips of leaves will turn white after being chilled at low temperature. Prevention and control measures: For the onion cultivation of green onions, pay attention to water cooling; greenhouse cultivation should be strengthened ventilation, to prevent the emergence of high temperatures above 30 °C. Low temperature period to enhance insulation. 5, toxic gas hazard caused by dry tip in the case of confined application of ammonium sulfate or ammonium chloride, will cause ammonia hazards, soil acidification caused by nitrite gas hazards. Ammonia hazards cause the tips of the leaves to wither and gradually turn brown; nitrous oxide gas damages the tips of the leaves and leaves them dead. Prevention measures: (1) release air. (2) Increase organic fertilizer. In the case where the airtightness cannot be ventilated, ammonium carbonate is not topped. (3) Use the original EM original dew root or spray to relieve the hazard. The specific usage is to use 500 times liquid to irrigate the root once; use 1000 times liquid to spray once every 7 days and spray twice. 6, drug injury caused by dry tip concentration is too high, so that the tip of the white, dry. Control measures: master reasonable liquid concentration, spray 0.05% nucleotide AS (green wind 95) 500 times, or use Teijin EM 500-800 times solution in early morning or evening spray, once every 7 days, even Spray 2-3 times. Second, pathological dry tip The pathological dry tip refers to the dry tip caused by Welsh onion and Downy mildew. Botrytis cinerea Tip: At the beginning of the disease, white spots appear on the leaves, which mostly develop downward from the tips of the leaves, and can extend downwards by 2 to 3 cm and dry. Humidity produces large amounts of gray mold on dead leaves. The dry tip of downy mildew: the leaves are affected and begin to produce oval or elliptic lesions, initially yellowish-white, and later turned grayish. When the humidity is high, a white thin layer of mildew develops on the surface of the lesion. Prevention and control measures: There are mainly agricultural measures, physical measures, and chemical measures. 2. Physically-restricted areas can use drop-free or UV-blocking membranes to reduce the incidence. In addition, the damage of seed fly can also cause dry tip, and the fly larvae damage the onion root and cause the tip of the shoot to dry. Should strengthen the forecast and forecast, seize the adult spawning peak and incubation period timely prevention and treatment. The method of attracting adult worms is that the ratio of sweet and sour water is 1:1:2.5, and a small amount of 90% trichlorfon crystal is added into the container. In adult stage, 2.5% deltamethrin EC3000 was used to control. Frozen Squid Flower Cut,Frozen Squid Flower,Squid Carving Flower,Pineapple Cut Squid Flower Zhoushan Haiwang Seafood Co., Ltd. , https://www.haiwangseafoods.com
1. Agricultural Measures 1 Use disease-free seed or seed disinfection. Selection should be done on a disease-free plot. Seed disinfection method is to use 50 °C warm water soak for 30 minutes to remove, put into cold water cooling, remove and germination, sowing. 2 Implement rotations. More than 2 years of rotation with non-lilytical vegetables, turning the soil deep. 3 Rational cultivation. Choose high-lying, well-drained land for planting; adopt high or half-high ridge cultivation, and plant densely and densely; choose sunny morning watering, timely drainage after rain, protect the green onion as much as possible using drip irrigation or pouring dark water under the plastic film; Organic fertilizer, increase phosphorus and potassium fertilizers. 4 strengthen ventilation, light transmission, pay attention to warming and heat preservation. Onions cultivated on protected areas should pay attention to excreting moisture, especially after watering, strengthen the ventilation, reduce the humidity inside the greenhouse, and the occurrence of unfavorable diseases; when the outside temperature is low, it is necessary to do a good job of increasing temperature, insulation, and reducing the number of sheds. , Night temperature difference, control of leaf condensation, can reduce the incidence. 5 field cleaning. The timely removal of diseased leaves and diseased bodies brings deep burial or burning out of fields, which can reduce the spread of germs.
3, chemical measures 1 smoked. Protecting green onions, before or at the beginning of gray mold, use 20% of ethylene nucleus to kill FU or 15% of procymidone FU (sulferyl), 20% of chlorothalonil FU before the onset of downy mildew, 15 at the early stage of onset. % Cream urea. Manganese zinc FU (Kelu) smoked. 2 dust. Protected green onions, Botrytis at the beginning of the onset of disease, 5% of B. mildew P1 kg, 5% of chlorothalonil at the onset of downy mildew, and 5% of noxious manganese zinc (FU) at the beginning of the disease. Spray powder, nozzle up, can not be directly on the onion spray, spray onion above the space, so that dust falls on the onion. 3 spray. In the early stage of the disease, 50% iprodione WP (promethine) 1000-1500 times solution or 50% procymidone WP (sikorin) 1500 times solution is used for spraying, and 50% of procymidone WP1500 times can be used later. +% Thiophanate-methyl WP (thiophanate-methyl) 500-fold spray control. In the early stage of downy mildew, 40% phosphine aluminum WP 400 times, at the later stage of disease, can be used 72.0% Proploacycin AS (Precise) 600-800 times or 72% Manganese Zinc Cream urea WP (Kelu) 600-800 times Liquid, 40% Ethylphosphine WP + 64% Anti-virus WP400-600 Liquid Spray Control.