Improve the level of disease management and increase the economic benefits of greenhouses

At present, the north is about to enter the severe winter season. It is the early stage of flowering of the greenhouse vegetable greenhouse, and it is also the key period for greenhouse management and disease prevention. To this end, the reporter specially organized this draft to help dealers and farmers do a good job in greenhouse disease management and improve economic efficiency.

1. Three main causes of serious diseases in greenhouses

First of all, temperature and humidity management errors. Most vegetable farmers started to ventilate around 10 am, and closed the air outlet in the morning and night. As a result, the temperature in the greenhouse was low and the relative humidity of the air was high. The most suitable temperature for the development of most diseases is 15-26 °C. In this way, the temperature in the shed is about 20 °C for a long time, and the humidity is above 90%, which is just the most suitable for the occurrence of diseases.

Second, low temperature management results in low soil temperatures. Under this management mode, the soil temperature is around 20 °C or even lower for a long time. The soil temperature is low, the root system is poorly developed, affecting the absorption capacity, resulting in poor resistance of plants. Solving various disease problems from the "roots" is also the root of disease prevention and control that agricultural experts have been advocating. When the roots are healthy, they can flourish, and thus fundamentally improve the resistance of crops and resist disease.

Second, the pathogens were not eliminated and controlled in a timely and thorough manner. This has been getting better and better with the awareness of vegetable farmers to prevent pests and diseases. In some mature planting areas, almost no diseased leaves, diseased fruits, and alfalfa are found in greenhouses. However, it is worth noting that even if these are cleared out of the greenhouse, they need to be buried, fattened or burned in time, because when the greenhouse is ventilated, the bacteria can be introduced into the shed from the tuyere, causing recurrence.

2. Temperature and humidity regulation is the best way to prevent disease

In addition to regularly spraying protective fungicides during safe intervals, the creation of high-temperature, low-humidity ecological environment is the most important and the main measure for ecological control. Generally speaking, the humidity in the greenhouse is higher than 90% at night. After pulling the grass in the morning, the vents should be opened and ventilated immediately. After 9 o'clock, when the temperature in the shed rises, the vent is closed, and the temperature in the shed is quickly raised to 2-3 °C higher than the upper limit of the maximum growth temperature of the crop, and the temperature is maintained as high as 15-16. After 15-16 hours, gradually increase the vents to accelerate the drainage. Before covering the grasshopper, as long as the temperature in the shed is not lower than 16 °C, the vent should be increased as much as possible; if the temperature is lower than 16 °C, the vent should be closed in time. Moreover, under the premise of ensuring that the temperature in the shed in the early morning is not lower than 10 °C, the tuyere can be opened again from below the grasshopper at around 21-22 hours to minimize the humidity in the shed. In the above temperature and humidity control process, when the temperature is high, the humidity is low, and when the humidity is high, the temperature is low, which can effectively suppress the occurrence of diseases, reduce the number of medications and the amount of medication.

3. Reasonably adjust the vegetable marketing season

In general, the price of vegetables before and after the Spring Festival is the highest in a year, so the solanaceous vegetables can be properly adjusted in cultivation to reach the harvest period before and after the Spring Festival. The specific method can be achieved by adjusting the sowing date and adjusting the relationship between vegetative growth and reproductive growth. This requires more careful management, and the prevention and control of pests and diseases can not be relaxed. When using the temperature in the shed to regulate the growth rate of the crop, it is necessary to ensure that the temperature of the soil cannot be too low, so as to avoid the dysplasia of the root system and cause sudden disease.

Management instance

Early grafting of Cucumber grafting against Aspergillus fumigatus

Cucumber grafting technology has been widely promoted. Generally, black seed pumpkin is used as a rootstock. Grafting effectively overcomes the continuous cropping obstacle of cucumber, which prevents the occurrence of blight. The problem to be noted after grafting is that after grafting, the root of the cucumber must be removed, otherwise the root of the black seed pumpkin will grow poorly, the interface will not heal well, and the root of the cucumber will also be infected with blight.

Cucumber gray mold, downy mildew and bacterial angular spot disease are the most important issues in cucumber production before the Spring Festival. These diseases develop rapidly and have strong destructive ability. Among them, downy mildew and bacterial angular spot damage are harmful to cucumber leaves, while gray mold damages flowers, young fruits, stems and leaves, etc., to harm flowers and young fruits. Several diseases have similarities due to their occurrence and can be controlled at the same time.

Cucumber is a typical representative of Cucurbitaceae vegetables. Other cucurbit vegetables such as zucchini, watermelon, melon, and bitter gourd need to be grafted and cultivated to resist the occurrence of blight. In addition to blight, the powdery mildew of melons is more harmful. Keeping the greenhouse ventilated and transparent, and not applying nitrogen fertilizer can reduce the incidence of disease. At the time of onset, it is necessary to spray drugs as early as possible in the early stage of the disease to achieve a multiplier effect.

Tomato physiological diseases should pay attention to the fine management of pepper

Compared with cucumber, tomato has a developed root system and strong absorption capacity. Its life span in greenhouses can be as long as 2-3 years, and the yield is extremely high. In terms of management, tomatoes are less sensitive to water and fertilizer than cucumbers, and they are more extensive than cucumbers in cultivation management.

The diseases of tomato in this period mainly include early, late blight and gray mold. The temperature and humidity control is similar to that of cucumber, except that the upper limit of tomato temperature is lower than that of cucumber. When the air outlet is closed in the morning, the temperature in the shed reaches 30. -32 ° C can be.

In addition to several common diseases, tomato physiological diseases and viral diseases have become more and more serious in recent years, such as umbilical rot, tendon rot, malformed fruit, and leaf rolling disease. Most of the causes of these diseases are caused by the combined effects of various adverse conditions. Low temperature, high temperature, low light, high night temperature, potassium deficiency, excessive nitrogen fertilizer, etc. can cause these diseases to occur. In order to prevent the occurrence of such diseases, comprehensive measures should be taken. On the basis of reasonable regulation of temperature and humidity, reasonable fertilization and topdressing, proper thinning, improvement of lighting conditions in the shed (pruning and forking), and selection of appropriate concentration of scorpion hormonal drugs are also needed. Liquid, etc.

Other solanaceous crops such as pepper and eggplant are also high-efficiency species for winter cultivation. Peppers should be controlled at 28-30 °C and eggplant at 26-28 °C. The root of pepper is shallow, not drought-tolerant, not resistant to phlegm, not only high temperature but also low temperature, so it is more careful than tomato and eggplant in cultivation management. On the basis of correct control of temperature and humidity, regular spraying of protective fungicides can limit the occurrence of various diseases; prevention and control of viral diseases should simultaneously treat aphids, and try to avoid damage caused by farming operations.