What measures should be taken to deal with the influence of bad weather when planting vegetables in greenhouses?

After several days of high temperature above 30℃, it ushered in cool rainy weather, and the temperature dropped by nearly half to 13℃~ 15℃, which had a great impact on the cultivation of fruits and vegetables in greenhouses. For example, the stress resistance of vegetables is reduced, and the fruits in the sugar color period are cracked, and some diseases will be aggravated. Therefore, it is necessary for us to take some measures to actively deal with the adverse effects of bad weather on greenhouse vegetables in China.

First, the reduction of vegetable stress resistance and countermeasures

The rapidly changing weather has the greatest impact on vegetables, which is the decrease of stress resistance, and the direct manifestation of the decrease of stress resistance is a series of adverse reactions of plants. The sudden high temperature the other day was a disastrous weather for our vegetables. The temperature in the greenhouse can easily reach above 40℃, which will lead to the sudden increase of nutrient consumption of our vegetables and the emergence of leaf senescence, including leaf burn, physiological water loss and other symptoms. In recent days, many vegetable farmers have asked such questions. Then it suddenly cooled down, and the high and low weather made it difficult for vegetables to adapt, resulting in a continuous decline in the resistance of vegetables.

Countermeasures: Spraying foliar fertilizer in time can improve the stress resistance of vegetables. It is suggested to spray some organic water-soluble fertilizers containing amino acids and trace elements to enhance plant metabolism and cell division. Amino acids and small molecular peptides can be quickly absorbed by crops, which can quickly supplement nutrients to crops and repair damaged cells, thus promoting the physiological development of plants to achieve the best growth state from unfavorable factors and improving the stress resistance of vegetables and plants.

Second, the cracking of crops in colored sugar stage and its countermeasures

For some crops in the colored sugar period, such as tomatoes, melons, watermelons, etc., after entering the colored sugar period, this sudden temperature rise and fall directly from the original medium-low temperature to the high temperature, and then directly from the high temperature to the extremely low temperature, which has a great impact on the fruit and is likely to lead to fruit cracking or melon cracking.

There are two reasons for cracking fruit and melon. First, the rapid change of temperature will lead to the imbalance of the growth and development of pulp tissue and pericarp tissue; Second, the temperature will lead to calcium absorption disorders in crops. Both of them can cause fruit cracking or melon cracking.

Countermeasures: In view of the phenomenon of melon cracking and fruit cracking in colored crops during sugar period, we suggest spraying water-soluble fertilizer containing chelated calcium and magnesium directly twice in a row, and increasing the thickness of intercellular pectin layer through rapid calcium supplementation to alleviate melon cracking and fruit cracking caused by serious temperature difference; By rapidly supplementing magnesium, chlorophyll synthesis is promoted, photosynthesis is enhanced, and fruits become bigger.

Third, large-scale diseases and countermeasures

Due to the temperature drop and rainy weather, the humidity in the shed has increased greatly. The recent high and low temperatures have led to a continuous decline in the stress resistance of vegetables, which will lead to a large area of bacterial diseases and fungal diseases in the lower part. Generally speaking, for normal weather, bacterial diseases such as downy mildew and epidemic diseases and lower fungal diseases should not be particularly serious or will not happen again after May. But now this weather will lead to bacterial diseases, downy mildew and epidemics. Such as melon canker, leaf blight and downy mildew; Late blight of tomato; Cucumber downy mildew, leaf blight and so on, these diseases will be biased.

Response measures:

In view of these diseases, it is suggested that vegetable farmers pay attention to prevention and control.

1. No diseases occurred in the shed.

If there is no illness in the shed, it doesn't mean that everything is fine. We should actively do a good job in prevention. It can be controlled by spraying kasugamycin+propamocarb+pyraclostrobin+cymoxanil for about 10 day.

There is a disease in the shed.

If there is a disease in the shed, we should treat it according to different diseases.

Bacterial diseases: For bacterial diseases, it is recommended to use the medicine containing Bacillus subtilis+kasugamycin+copper quinoline for treatment, spraying 1 time for 4~5 days, twice in a row. Whether it is canker, leaf blight, angular leaf spot, etc. As long as it is a bacterial disease, it can be treated according to this plan. Lower fungal diseases: Lower fungal diseases are mainly downy mildew and epidemic diseases. It is suggested to directly spray the drugs containing the effective components of Cyanazole+dimethomorph+cymoxanil for treatment, and continue to fight twice within 5 days. By spraying, lower fungal diseases can be completely controlled. Higher fungal diseases: In this period, anthracnose and target spot disease in higher fungal diseases are also high-incidence diseases, especially target spot disease of cucumber, which will occur more frequently at this time. In view of this kind of disease, it is suggested to use the drug containing difenoconazole+prochloraz+thiophanate-methyl as the effective ingredient for treatment, and this kind of disease will be cured. In addition, in view of these diseases, we should pay attention to the ventilation in the shed while preventing them. At this time, even if it is cloudy, it should be ventilated. Many of our vegetable farmers feel that the temperature is low, so they like to make the shed stuffy, which will lead to the increasing humidity in the shed and the increasing probability of diseases. If it has already happened, it will lead to the aggravation of the disease. Therefore, it is necessary to ventilate a small area in time. When the temperature is low, we can turn down the air outlet. The purpose is not to ventilate, but to discharge part of the humidity in the shed and reduce the humidity in the shed. This is indispensable.

In a word, the drastic changes in the weather these days have brought many adverse effects on the cultivation of fruits and vegetables in our greenhouse. However, as long as we improve the stress resistance by spraying foliar fertilizer, prevent fruits and vegetables from cracking and melon cracking by supplementing calcium during the coloring and sugar adding period, and prevent diseases at the same time, we can minimize the impact of adverse weather on our greenhouse crops.