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For many years, the prevention and control of diseases and insect pests has advocated the principle of harmless prevention and control with " agricultural control, physical control, biological control, supplemented by chemical control". However, if you want stable and high-yield vegetables in greenhouses, and you inevitably use a variety of pesticides, how should you choose and apply pesticides in greenhouse vegetable planting ? What should you pay attention to when selecting and applying medicine?
1. Scientific and rational use of medicines to delay the development of drug resistance.
1. Avoid long-term single drug use and choose new varieties of pesticides
It is easy for a single drug to develop resistance to diseases and insect pests. Reduced effectiveness. The new variety (which is not often used in the shed) can reduce the number of medications, reduce production costs, improve control effects, and slow down the development of drug resistance.
2. Grasp the proper dosage and concentration
In general, the higher the concentration of the drug, the better the efficacy. What is a slow-release pesticide? However, too high a concentration of the drug causes residues of the drug to easily cause drug damage, and it also increases the resistance of the bacteria. The preparation of multiples of the medicinal solution should be performed strictly in accordance with the instructions.
3. Control the frequency of application and master the reasonable interval
Too many times of excessive application, too short interval, easy to produce harm. The effective period of general chemical agents is 7-10 days, so the interval between each time should be 7-10 days. Greenhouse vegetables are applied 2-3 times a month, not more than 4 times.
Second, seize the critical period of disease prevention and achieve early prevention.
1. The first critical period is the seedling stage. During the seedling raising period, the seedlings are small, disease resistance is weak and susceptible to infection by germs. Protective fungicides such as chlorothalonil and mancozeb should be sprayed once to ensure that the seedlings are not infected by the germs.
2. The second critical period is after the planting of the delayed seedlings. After the seedlings are retarded, the plant growth speed is accelerated, and the disease is prone to occur. A protective spray should be performed to form a protective film around the plant to prevent the infection of the bacteria.
3. The third key period is the young fruit period. After flowering and fruiting, the period from vegetative growth to reproductive growth and vegetative growth go hand in hand. Leaf nutrition is poor and susceptible to disease. It should be sprayed in time to control.
4. The fourth key period is the harvest period. During the harvest period, most of the nutrients absorbed by the plant were taken away by the fruit, and the disease resistance of the plant was significantly weakened. At the same time, the number of waterings increased, the humidity in the shed was high, and it was prone to disease. Therefore, spray the medicine before watering to prevent it, and at the same time, carry out field inspection and find that the central diseased plant is immediately used for medicine.
3. Improve spraying technology to ensure the quality of medication.
1. Spray medicine should be comprehensive. When spraying, do not leak, re-spray, leak, or leak. Spray from the bottom of the plant upwards, spray evenly on both sides.
2. Grasp the point when spraying. The central susceptible disease around the plant should be sprayed, and the middle and upper leaves of the plant should be sprayed.
3. Determine the spray time. In general, when the light is strong, the temperature is high, and the crops have strong transpiration, respiration, and photosynthesis, the stomata on the surface of the stems and leaves are open, which is conducive to the entry of the medicine. In addition, the humidity of the surface of the large leaf is slow to dry and easy to use Absorption enhances the efficacy. However, too strong light and high temperature can easily cause photolysis or damage to the medicine, so it should not be sprayed around noon. In practice, the best application time is that the spraying effect is good when the temperature is 20-25 ° C and the humidity is 70-75% on a sunny morning.
4. Master scientific disease prevention and pay attention to the four principles of medication
1, timely medication. The pesticide should be applied in the early stage of the occurrence of pests and diseases, especially in the warm and humid environment of the shed. It is not suitable to spray the medicine in rainy days or high temperatures to prevent the temperature in the shed from being too high and reduce the efficacy. At the same time, do not use sulfur preparations to prevent diseases of melons and vegetables at high temperatures, so as to avoid drug damage.
2. Rotate medication. Different types of pesticides with different action mechanisms should be used alternately. For example, omethoate belongs to the organophosphorus pesticides and dicidium si belongs to the pyrethroid pesticides. They have different action mechanisms. If you pay attention to the rotation, you can avoid or delay the resistance of pests and diseases. produce.
3. Safe medication. In vegetable production, high-efficiency, low-toxicity, and low-residue pesticide varieties should be selected. Do not increase the concentration of the drug solution at will. Do not use too many times, and strictly follow the safety period. At the same time, the use of highly toxic pesticides such as organochlorine and furandan should be strictly prohibited.
4. Do not buy expired pesticides. When purchasing or using chemical pesticides, it is necessary to identify the quality of the pesticides. If purchased or used pesticides have expired, it will not only directly cause economic losses, but also easily cause drug damage.
October 16, 2017
Chengdu Xinxin Electronic Technology Co., Ltd. Editorial Department
Editor: Little Devil in Gourd