In winter, the temperature is low, and most of the pests and diseases are in a hidden state. If the medicine is used according to the conventional method, it is difficult to achieve the desired control effect. Therefore, we must pay attention to the following issues. Choose sunny day and high temperature application In general, the application of pesticides works best at 4 pm on sunny days, because plant leaves absorb the most liquids at the same time; in winter, they are different. It is best to apply them at high temperatures on sunny days. On the one hand, pests are in winter. When the temperature is high, the food intake and respiratory intensity are greater than the cold weather. The pests eat a large amount of food with the introduction of drugs; on the other hand, most pesticides at normal temperature, the higher the temperature, the better the effect. When microbial pesticides are used, the crystal proteins and living spores of the active components of the crop biopesticide are slow to propagate in the pests at low temperatures, and the protein crystals are not easy to function, and the effect is applied at 10 ° C to 15 ° C. It is less than 50% applied at 25 ° C ~ 30 ° C. When the herbicide is applied under low temperature conditions in winter, the weigh absorption ability of the weeds is not very strong, and the herbicide is slowly absorbed and decomposed by the weeds, and the effect is greatly reduced or even ineffective. When the herbicide is applied at a high temperature, the weeds absorb the herbicide at a high speed, a large amount, and the metabolic decomposition is difficult, and the purpose of weeding is easily achieved. But pay attention to not spray immediately after the sunny day, the weather suddenly turns fine, the crop leaves are thinned due to long-term photosynthesis is not strong, and yellow and tender, spraying is easy to produce phytotoxicity. Therefore, the greenhouse crop should be sprayed after 2~3 days of ventilation and light transmission, which can not only exert the efficacy but also cause phytotoxicity. Rational selection of chemical pesticides In general, stomach poisons and contact agents are less affected by temperature, and systemic and fumigants are more affected by temperature. The application of the herbicide at low temperatures in winter shows that the effect is much longer than that at high temperature, so wait patiently after administration. In addition, when applying pesticides under low temperature conditions, attention should be paid to the specificity of certain pesticides to crops, such as gray mold and sclerotinia disease in vegetables in winter, and the application of pyrimethanil to control eggplant and cowpea diseases. Small spots on the brown surface. Use appropriate application methods In the winter, pesticides should be used to control crop pests and diseases, and appropriate application methods should be adopted according to different situations. If the medicine is used in the shed, it should be applied by the smoke method or the dust method. If the spray method is applied, the number of times of prevention and the amount of liquid spray should be appropriately reduced. Otherwise, the humidity in the shed may be too large, which may cause a serious disease. It is worth noting that cloudy days do not smoke the shed. In the continuous cloudy sky, the air is not smooth, which may cause harmful gas accumulation. If the smoked shed is more likely to cause gas damage, the leaves of the young leaves of the vegetables will turn white or the leaves will turn yellow; After the damage, the flower buds, young fruit and so on are easy to fall off. Under continuous cloudy conditions, shed indoor vegetables are most prone to gray mold, sclerotinia, blight, downy mildew and bacterial diseases. It is a high incidence period of these diseases, and can not be rushed for success. It should be noted that these fungicides not only contain pyrimethanil, but also have the words "azole" and "alcohol". Therefore, it is necessary to strictly control the dosage, and it is best not to face the vegetable crop leaves or spray. Plant spraying to prevent phytotoxicity. Extended crop safety interval When pesticides are applied in winter, the degradation rate of pesticides is obviously slower, and the residual time in vegetable crops is relatively long. Under low temperature conditions, pesticides are sprayed on greenhouse vegetables. In order to ensure the health of consumers, special attention should be paid to prolonging the safety interval of pesticides. . When the temperature is lower than 20 °C, the greenhouse vegetables should not be applied to the insecticide , which not only affects the efficacy, but also the residue of the pesticide in the vegetable body is increased, which is unfavorable for ensuring human health. The optimum interval for most pesticides is about 10 days. If there is no special disease, it is best to spray once every 10 days. Be careful not to mix multiple pesticides at the same time. When the vegetable diseases in the greenhouse in the winter are serious, some farmers will spray the medicine once every 5 days, which is not advisable. Appropriate increase in dosage According to the determination, the lethal dose of pesticides to pests is not constant. At normal temperature, the higher the temperature, the lower the lethal dose of pests. Therefore, it is necessary to apply pesticides in the winter to increase the dosage appropriately, so as not to die after the pests are eaten. How much does the dosage increase? It is necessary to look at the temperature to determine how much the dosage is increased. Generally, it should not exceed 50% of the commonly used amount. When applying pesticides in winter, water should be added strictly according to the dilution factor. Do not increase or decrease the water. More pesticide knowledge , please pay attention to China Pesticide Network Graphite Ingot Mold,Molded Graphite Mold,Injection Molded Graphite,Molded Graphite Column Henan Carbons New Material Technology Co., Ltd. , https://www.hncarbons.com