Greenhouse leeks are prone to gray mold, and when they are severe, production is reduced by more than 30%, and the edible and commercial properties of leeks are reduced. After the onset of disease, the leaves from the tip of the tip gradually produce grayish brown to small white spots, both positive and negative, and after the expansion, they become elliptical or spindle-shaped lesions, and merge into large dead spots, when the humidity in the greenhouse is high, the disease department Gray or gray green mold layer; sometimes cut into the incision at the incision is semi-circular or inverted triangle rot, the diseased surface has a layer of mold. The air humidity is above 85% and the temperature is between 15°C and 20°C. Warm and humid conditions are favorable for this disease.
Pollution-free control measures:
1. Use resistant varieties. Broad-leaf disease-resistant varieties such as ferrets, 791, Xueqing, Hanqing, Jiaxing Baigen, etc.; narrow-leaved cold-resistant varieties such as wire seedlings, Ke mold 1, yellow seedlings, Zhongwan No. 2 and so on.
2. Strengthen field management. Using a small amount of water to help increase the temperature of the ground. After each harvest, 2 to 3 shallow cultivators are used to reduce the humidity in the shed. Timely release dampness. Grasp the time of harvest, harvest under conditions of low humidity and no dew, and then dry the roots and then earth. Timely removal of diseased leaves, increase fertilization, and enhance amaranth disease resistance.
3. Chemical control. Each mu with 10% fast Ke Ling smoke agent 250 grams smoke treatment, or 1000 grams per mu with 10% mildew powder spray, you can also use 50% Suo Keling wettable powder 1500 ~ 2000 times, 40% acetaminophen Wettable powder 1000-1500 times, 50% wettable powder 500 times, 50% thiophanate-methyl wettable powder 500 times, 70% mancozeb wettable powder 500 times spray control. In the initial stage of disease prevention and control once every 7 days, until the disease control. In the cultivation of cucumbers in winter greenhouses, the new leaves of the “head†of cucumber plants often appear to be rotten (ie, “rottenâ€). What are the causes of the cucumber rotten? How to prevent it?
First, black spot disease is the main reason causing cucumber rot
1. Symptom Identification: Cucumber scab is mainly harmful to the growing point of cucumber, and the incidence is rapid. Within a few days it can cause the heart to wither. There are three points in the recognition: one is the formation of stellate perforation in the lesions of the leaves, and the symptoms are obvious. Other phenomena do not have perforation; the second is the cracking of the stem lesions, and there is often a flow of colloidal material; the third is the lesions on the melon strips. Transparent gel-like flow out, followed by sores. Regardless of whether it is on the stem or on the melons, when the humidity is high, the disease minister has a layer of smoke and black mold.
2. Control methods: (1) Cultivation measures: Scab is a disease of low temperature and high humidity. During cultivation, attention should be paid to raising the temperature of the greenhouse, shortening the time for condensation on the surface of the leaf, covering the film, lowering the air and soil temperature, and promptly removing the shed. Inside the diseased body, it was burned outside the shed. (2) Chemical control: Use 25% DuPont Fuxing 8000x or 70% thiophanate-methyl 700x spray to control. In the early stage of onset, 50% carbendazim WP can be sprayed with 1000 times solution and 70% mancozeb WP wettable powder 1000 times. The effect is better. Do not leak the growth point when spraying.
Second, calcium deficient cucumber caused bad head
1. Symptom identification: The greenhouse soil generally does not lack calcium, but due to the slow absorption and transport of calcium, and the rapid growth of cucumber requires a large amount of calcium, easily lead to 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 calcium chloride 300 to 500 times liquid foliar spray, supplement the body's calcium nutrition.
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