Occurrence and Non-pollution Control of Cucumber

Cucumber leaf blight is an important disease commonly occurring in cucumber cultivation. In recent years, it has been on the rise, and it has occurred in both protected areas and exposed cucumbers. It often causes wilting in whole ridges of vines in a short period of time. In particular, the occurrence of high temperature and heavy rain often occurs, which has a great impact on the yield and seriously threatens cucumber production. The disease also harms melons, melons, melons, loofahs and other melons. First, the symptoms. Stems, leaves, and fruits can all be harmed. When the stem is damaged, it appears as a greasy lesion, elliptical or prismatic, close to the node of the stem, grayish white, slightly concave, secreting an amber jelly. When dry, the diseased part shrivelled, and the longitudinal cracks were messy. The surface was scattered with a large number of small black spots. The lesion spreads faster when wet, and one circle around the stem causes the upper half of the plant to wilt and die and the diseased part to rot. The lesions on the leaves are nearly round, sometimes "V"-shaped or semi-circular, pale brown to yellow-brown, with many small black spots on the lesions, and the later lesions are easily broken, and the lesion spots are not obvious. The fruits were mostly infected by flower buds during the young period, and the flesh was soft brown and heart-shaped. Second, the law of occurrence: The disease caused by Ascomycete fungus, seed carrier bacteria and soil disease residue carriers are the primary infestation source, wind and rain and irrigation water for the disease vector. The bacteria invade through the stomata, water holes, and wounds, and the seed bacteria can directly infect the cotyledons. The average temperature is 18-25°C, and the relative humidity is higher than 85%. The soil moisture content is high, and it is most susceptible to disease. Melons are heavily planted, densely planted, with excessive nitrogen fertilizer application, poor ventilation in the field, or insufficient fertilizer, and declining growth will aggravate the occurrence of diseases. The cultivation of open field occurs mainly in the summer and autumn rain seasons. Rainy days, or sudden clear rain, and hot weather, it is easy to cause epidemic. Third, pollution-free control measures 1, selection of disease-resistant, disease-resistant varieties. Jinyou No. 2, Jinyou No. 3, Nongda No. 12, Nongdaqiu No. 1, Nongda No. 32, Jinza No. 1, Jinyan No. 2 and Zhongnong No. 5 had good disease resistance. Can be chosen according to local conditions. 2, seed processing. Use disease-free seeds. Seeds are soaked in warm water (55°C) for 15 minutes before sowing. After soaking, they are soaked in cold water for 2-4 hours and then sowed with germination, or with 50% omeprazole WP at a seed weight of 0.3%. Seed dressing. 3, the implementation of rotation. It is best to implement 2-3 year non-guatem crop rotation. 4, strengthen the cultivation and management. Increase organic fertilizers, timely top dressing, in the application of nitrogen fertilizer with phosphorus and potassium fertilizers, promote plant growth robust. Timely pruning and timely harvesting. Protected cultivation should be centered on the reduction of humidity, mulching mulch film, under the film dark irrigation, rational close planting, strengthen ventilation and light transmission, reduce indoor humidity and dripping. Exposed cultivation to avoid flooding. In the rainy season, flood prevention is strengthened to reduce soil moisture. Appropriate control of watering after onset. Remove the diseased leaves in time and completely remove the diseased body after the harvest to burn or bury it deeply. 5. Use high-efficiency, low-toxicity and low-residue medicaments to control. In the early stage of onset of disease prevention and treatment, 75% chlorothalonil WP can be used as 600 times solution, or 70% zein Zn WP 500 times, or 50% carbendazim WP 500 times, or 50% A. Kitobutzin WP 500 times, or 40% polysulfide suspension 400 times, etc., sprayed every 5-7 days, depending on the condition and spray 2-3 times. Focus on spraying the stems and leaves of the lower part of the melon pods and the ground. When the disease is severe, the stem lesions can be smeared with 70% Mancozeb Zinc WP 500 times. The effect is good. The cultivation of greenhouses can be fumigated with 45% chlorothalonil aerosol, with dosage of 110-180 grams per acre, 5-6 places, night-lighting in a closed greenhouse, smoke in 7 days, and smoking 3 times for ideal prevention and treatment. effect. China Agricultural Network Editor

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