In the cultivation of cucumbers in winter greenhouses, the new leaves of the “head” of cucumber plants often appear to be rotten (ie, “rotten”). What is the cause of the bad head of cucumber? How to prevent it?
First, black sceen causes bad head of cucumber
1. Symptom identification. The formation of stellate perforation in the lesions of the leaves, the symptoms are obvious; the stem lesions are cracked, and there is often a gum flow out; the lesions on the melon strips have a clear gel-like flow out, followed by a scab-like appearance; the growth spots become infected, after two or three days Rotten to form bald piles. When the humidity is high, the disease minister has a layer of smoke and black mold.
2. Control methods. (1) Agricultural control: During the cultivation, attention should be paid to raising the temperature of the greenhouse, shortening the time of condensation on the surface of the leaves, covering the film, lowering the temperature of the air and the soil, removing the diseased bodies in the shed in time, and burning them outside the shed. (2) Chemical control: 70% thiophanate-methyl 700 times spray control; 50% carbendazim wettable powder 1000 times liquid plus 70% mancozeb WP wettable powder 1000 times When spraying, do not spray evenly when spraying.
Second, calcium deficiency caused by the bad head of cucumber
1. Symptom identification. The greenhouse soil is generally not deficient in calcium, but due to the slow absorption and transport of calcium, and the rapid growth of cucumber requires a large amount of calcium, which is likely to cause calcium deficiency. The symptoms of rotten head caused by calcium deprivation showed that the leaves near the growth point were cup-shaped and the leaf margin curled to death.
2. Control measures. When greenhouse cultivation, strictly control the amount of nitrogen fertilizer, pay attention to insulation; while using 300-500 times calcium chloride leaf spray, supplement the body's calcium nutrition.
Bacterial edge blight causes bad head of cucumber
1. Symptom identification. Bacterial edge blight is easy to attack in the cold season. The disease caused by the disease symptoms of cucumber rotten head disease infection, the invasion from the new leaf edge, causing the edge of leaves dry, leaf veins folds, leaf curling. The first occurrence of fruit on the pedicel, water-stained lesions, and later become brown, yellow fruit withered, when the humidity is high, the disease overflows bacilli.
2. Control methods. Remove old leaves in time, clean the pastoral areas after harvest, remove the diseased bodies, and take them out of the field to destroy them, deepen the soil, and speed up the decomposition of the diseased bodies. 72% of agricultural streptomycin 3000 times or 77% of wettable micronized powder can be sprayed and sprayed at 400 times, once every 5-7 days, and sprayed 3-4 times.
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