It is necessary to prevent four kinds of diseases when planting cucumber in greenhouse in winter.

In recent years, the variety of cucumber diseases in winter shed increased year by year, which caused different degrees of damage to cucumber production. The symptoms and control experience of several diseases and insect pests were introduced for reference of vegetable farmers.

Bacterial angular spot disease onset for the initial bright green water-like spots, gradually turning pale brown, spots by the vein restrictions were angular, gray-brown or yellow-brown, when humidity is large, the back of the leaves overflow with milky turbid water droplets of bacteria, dry with white marks, the disease is fragile and easy to perforate. Stems, petioles and fruits of the disease spots for water-like round spots, wet when there is white mucus, dry white. Control: can be in the early stage of disease with agricultural streptomycin soluble powder 1000 times solution, or 30% DT fungicide 500 times solution, or 5% chlorothalonil dust 1000 times solution spray, control effect is higher.

Fusarium wilt is extremely strong and can survive in the soil for more than 5 years. High temperature and humidity are favorable conditions for blight occurrence. Excessive nitrogen fertilizer, acid soil disease more serious. Root-knot nematodes were more serious in the plots with more root-knot nematodes and flooded plots. Prevention: In addition to selecting disease-resistant varieties, rotation with non-melon vegetable crops for more than 3 years can be adopted to reduce the accumulation of pathogenic bacteria in the soil; in the early stage of disease, spray 500 times solution of 50% carbendazim WP or 800 times solution of 70% thiophanate-methyl WP, or irrigate roots with 1000 times solution of 70% dixon WP or 800 times solution of 50% Likujing, 250 ml per plant, once every 7 days, 3 times continuously. Grafting is also an ideal method to control cucumber wilt. With sunspot pumpkin with developed root system and low temperature resistance to wilt as rootstock, cucumber as scion, grafting or grafting, the disease prevention effect is excellent.

At the initial stage of downy mildew, water-soaked yellowish irregular spots appeared on the back or edge of leaves. With the development of downy mildew, the spots gradually expanded and were restricted by veins to form polygonal macula. When the disease is serious, small spots merge into large spots, and gray black mold layer grows on the back of the spots under wet conditions. The diseased leaves develop from bottom to top, and the whole plant leaves die when it is serious. Prevention and control: first of all, we should apply sufficient base fertilizer, appropriately increase phosphorus and potassium fertilizer, cultivate strong seedlings, water under the film, and reduce the number of watering. Enhance ventilation and reduce air humidity. The second is chemical control, specifically, 25% Ruidumei WP 800~1000 times solution, 75% chlorothalonil WP 500~600 times solution, 72% Kelu WP 600~800 times solution, 72% Prik 600~1000 times solution spray. Can also use 20~30 grams of chlorothalonil smoke agent fumigation shed per mu each time. Every 7~10 days once, continuous prevention and treatment 3~5 times.

Root knot nematode disease symptoms of cucumber root knot nematode disease is mainly manifested in the root, mild disease symptoms are not obvious, serious disease plants are shorter, poor development, poor seed, wilting at noon under drought conditions. Pulling up diseased melon seedlings will reveal tuberous roots of varying sizes on lateral roots or fibrous roots. Some appear beaded occurrence, make root system thickens, dissect root knot, can discover very small milky white root knot nematode inside diseased part organization. Prevention and control: deep turning of the soil, irrigation in idle time, increased application of decomposed organic fertilizer and other methods, cucumber root knot nematode disease occurs during growth, can choose 50% phoxim EC 1500 times solution or 30% Jiasheng microcapsule suspension emulsion 500 times solution irrigation roots, each plant irrigation 0.25~0.5 kg, generally irrigation once.