Late blight is the main disease of greenhouse tomatoes, which should be detected early, removed early, prevented early, and cured early.

Symptoms: Tomato late blight can occur from the seedling stage to the fruiting stage, which harms the leaves and damages the stems and fruits, and the leaves and fruits are the most seriously damaged. Generally, the disease begins from the front end of the shed, first infecting the leaves and young fruit, and gradually spreading to the stalk and petiole to make it dark brown. In severe cases, the plant is wilted and broken. The fruit of the diseased fruit is hard and uneven, and the initial stage is oily and dark green, and then becomes dark brown to tan. Under normal circumstances, the susceptible fruit does not become soft and rot. When the humidity is high, white mildew can be seen at the border between the front and the back of the leaf.

Incidence conditions: tomato late blight is a kind of low-temperature and high-humidity disease. The temperature in the greenhouse is 22~24°C during the day, 10~13°C during the night, and the relative humidity of the air above 80% can infect the plants. In the morning and evening, the fog is heavy, the dew is heavy, or the rain is heavy and the humidity is high. The disease develops rapidly, and once it is discovered, it must be prevented as soon as possible.

Prevention:

1. Select varieties that are resistant to disease and disease, and the ward can be used for more than 3 years.

2. High-mulch mulching cultivation; suitable planting density, not too dense, early scaffolding, timely pruning, appropriate removal of old leaves, yellow leaves and diseased leaves in the lower part of the plant to improve ventilation and light transmission conditions. Formulated fertilization technology, combined with nitrogen, phosphorus and potassium fertilizers, the application of potassium fertilizer has the effect of reducing the incidence. Pay attention to reasonable irrigation, avoid flooding.

3. After the grass curtain is exposed every morning, check the leaves and fruits of the tomato in the shed, focus on the tomato 1 to 2 meters in front of the shed, and find the central diseased plant, immediately remove the plant or remove the diseased leaves and diseased fruit. Deeply buried or burned outside the shed, reducing field spread and controlling disease occurrence.

4. Temperature and humidity regulation. The tomato fruiting period requires a daytime temperature of 25 to 30 ° C, a night temperature of 12 to 15 ° C, and a minimum temperature of not less than 10 ° C. On a sunny day, when the indoor temperature reaches 30 °C, the air is released in time, and at low temperature, the air is released for a short time.

5. Scientific medication. In the field, the diseased plants in the center should be removed, and the diseased leaves and diseased fruits should be removed. 50% Anke·Mn-Zn wettable powder 500 times solution, 72% gram dew wettable powder 800 times solution, 72.2% Plex aqueous solution 800 times solution or 58% toxic manganese-zinc wettable powder 500 times liquid spray. Leaf back, stalk, green fruit, etc. should be sprayed everywhere. The middle and lower parts of the plant are the key spray areas, and they should be rotated. Pay attention to the time in the morning when you fight. In the afternoon, the medicine is sprayed, the water does not disperse, and the humidity is high, which is not good for disease prevention. In the event of rain and snow, dust or smoke agents can be used for prevention and control. Dust method: 1 kg of powder with 5% chlorothalonil dust. Tobacco method: 45% bactericidal smoke agent or 10% quick ketone smoke agent 200 ~ 250 grams of smoked shed.


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Wing Screws

After installing the nut and Bolt in place, insert the locking bar from the groove of the bolt and make the V-shaped teeth of the locking bar snap into one of the V-shaped grooves, then push the whole locking bar into the groove, as the V-shaped teeth are stuck in the nut.

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