Impact of 2 types of El Niño events and La Niña events on the occurrence degree and immigration period of <i>Nilaparvata lugens</i> (Stål) in the rice-growing regions of South China

The immigration and catastrophic damage caused by brown planthopper, Nilaparvata lugens (Stål) (N. lugens), have posed serious threats to rice production in China since the 1970s because of the influence of El Niño events and La Niña events, as well as anomalies in the spatiotemporal distributions of planthopper immigration and damage. However, the mechanisms through which El Niño events and La Niña events affect N. lugens dynamics remain understudied, especially with the emergence of new El Niño events and new La Niña event types. We analyzed the effects of 4 ENSO event types on the occurrence degree and immigration period of N. lugens in South China via N. lugens light-trap catches and meteorological data from 1979 to 2020. The results revealed that central Pacific (CP) El Niño events imposed significantly different effects on N. lugens occurrence than did eastern Pacific (EP) El Niño events. There was no significant difference between CP and EP La Niña events, more of an interdecadal variation. The atmospheric circulation during El Niño events was more suitable for N. lugens immigration. The differences between the different El Niño event types were due to differences in the locations of sea surface temperature anomalies on the Pacific Ocean, vertical motion in the atmosphere, and differential dynamics of the Western Pacific subtropical high. These results indicate the importance of predicting 2 types of El Niño events and La Niña events before or during N. lugens immigration to South China and reflect the complex relationship between N. lugens occurrence and atmospheric motion.