China is a country with serious natural disasters, and crop diseases and insect pests are one of the main natural disasters in China. It has the characteristics of many kinds, great influence and frequent outbreaks. There are more than 1400 kinds of important crop pests and diseases in China, among which there are more than 20 kinds of major epidemic and migratory pests and diseases. The occurrence, development and prevalence of almost all large-scale, explosive and destructive major crop diseases and insect pests are closely related to meteorological conditions or accompanied by meteorological disasters. The occurrence, development and prevalence of crop diseases and insect pests must meet the following three conditions at the same time: first, there are host plants that breed and feed on diseases and insect pests; Second, pests and diseases themselves are in the development stage of their ability to harm crops; Third, there is an environment suitable for the further development and spread of pests and diseases, among which meteorological conditions are the key factors to determine the occurrence and prevalence of pests and diseases. Pests and Meteorological Conditions —— The main meteorological factors for the growth, reproduction and migration of pests are temperature, precipitation, humidity, light and wind. In particular, their comprehensive effects play an important role in the occurrence and development of pests. These meteorological factors also indirectly affect the occurrence and harm of pests by affecting the growth and reproduction of host crops and natural enemies. Temperature: The activities of crop pests need a certain suitable temperature range, generally 6℃-36℃. In the suitable temperature range, the development speed of pests increases linearly with the increase of temperature, and pests have vigorous life activities, long life span and more offspring. Humidity and rainfall: Humidity and rainfall are the main factors affecting the change of pest population. The influence on the growth and reproduction of pests varies with the species of pests. Humidity-loving pests require high humidity (relative humidity ≥ 70%), while dryness-loving pests require low humidity (relative humidity < 50%). For example, abundant rain, high relative humidity and mild climate in spring are often conducive to the occurrence of corn borer. Illumination: the influence on pests is mainly manifested in three aspects: light wave, light intensity and photoperiod: light wave is closely related to the phototaxis of pests; The light intensity mainly affects the day and night rhythmic behavior of pests, such as feeding, perching, mating and spawning, which is related to the body color and concentration of pests. Photoperiod is an important factor leading to diapause and dormancy of pests. The brief light in nature will stimulate pests to sleep. Wind: Wind is closely related to the feeding and migration of pests. Generally, weak wind energy stimulates take-off, while strong wind inhibits take-off; The migration speed and direction are basically consistent with the wind speed and direction. Diseases and Meteorological Conditions-The main meteorological factors for the occurrence and development of diseases are temperature, precipitation, humidity and wind, and unfavorable conditions such as low temperature, rainy weather, drought and strong wind will obviously affect the disease resistance of host crops. Grasping the law between the occurrence of diseases and insect pests and meteorological conditions, we can use the previous meteorological factors and insect pests to predict the occurrence of future diseases and insect pests.

Crop diseases and insect pests are closely related to meteorology.