Due to the low temperature in winter, the activities and damages of diseases and insect pests are mostly hidden and static. The following points should be paid special attention to in the prevention and control of vegetable diseases and insect pests

      In general, the influence of temperature on gastric agents and contact killers is less, while that of endosorbents and fumigants is greater. For example, low temperature such as dichlorvos and dichlorvos can significantly affect the insecticidal effect, while deltamethrin, phoxim, stone sulfur mixture and other pesticides can still play a better insecticidal effect at lower temperature. Therefore, it is necessary to select pesticides which are less affected by temperature in winter.

       Because when the temperature is high in winter, the range of activity and respiratory intensity of pests increase, and the amount of food taken increases. When the liquid is sprayed on the insect body, more drugs are brought into the body, which is conducive to play a toxic role.

The lower the temperature is at room temperature, the lower the lethal dose is. Therefore, increasing the dosage of pesticide in winter can prevent the pest from dying after taking the medicine. However, it should not exceed the "safe high concentration" (i.e. the maximum allowable dosage of no drug harm). When applying pesticides in winter, water should be added strictly according to the dilution ratio, and the amount of water should not be increased or reduced at will.

In winter, pest control in greenhouse crops should be smog or dust method. If spray is applied, we should reduce the frequency of prevention and control and spray volume, and prevent humidity in the shed.

In winter, the degradation rate of pesticides becomes slower, and the pesticide remains in the crop for a relatively long time. In order to prevent and control the diseases and insect pests of vegetable crops, it is necessary to extend the days between the last application of pesticide and harvest (i.e. safety interval) to ensure food safety.