The contrasting response of crop production and pest damage to ENSO cycles

Authors: WANG, LEYUN - China Agricultural University; Reddy, Gadi V.P.; ZHAO, ZIHUA - China Agricultural University

Submitted to: Entomologia Generalis
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/2/2022
Publication Date: 1/17/2023
Citation: Wang, L., Reddy, G.V., Zhao, Z. 2023. The contrasting response of crop production and pest damage to ENSO cycles. Entomologia Generalis. 43:1-11. https://doi.org/10.1127/entomologia/2022/1688.
DOI: https://doi.org/10.1127/entomologia/2022/1688

Interpretive Summary: Climate change involves both global warming and increases in extreme climatic events, and it has tremendous impacts on ecosystem functions and services. Examining how individuals and populations respond to climatic factors and large climatic phenomena is key to predicting the effects of climate change on ecosystem functions. Climate variables (e.g., temperature) have been monitored and described by specific climatic indices of ocean conditions, which can be good indicators of variation in both oceanic and terrestrial ecosystems. El Niño-Southern Oscillation (ENSO), which comprises three phases, the warming phase (El Niño), the cooling phase (La Niña), and the neutral phase in between, is a common and important large-scale climatic phenomenon that reflects the variation in the ocean surface temperature in the central and eastern tropical Pacific Ocean that has fundamental effects on the atmosphere and the surrounding terrestrial environment. 218 We found that oscillating crop yields and pest outbreaks can ultimately be related to ENSO cycles, whose global effects arise from variation in ocean surface temperatures in the central and eastern tropical Pacific Ocean and have fundamental impacts on the atmosphere. Our evidence demonstrates that crops with origins from different climatic regions can exhibit optimal thermal performance range-dependent responses to ENSO events. A cold-acclimated crop (wheat) benefits from the cooling ENSO phase in hot climates as well as from the warming ENSO phase in cold climates. Rice, a heat-acclimated crop, showed an inherent ability to use heat throughout growing seasons and was resilient to El Niño phases in the W-temperate, Tibet, and subtropical regions. Corn, the other heat-acclimated crop, was cultivated only in warmer seasons, and El Niño phases were more likely to cause heat stress in the growing seasons rather than promote growth in cold seasons, which resulted in net decreases in yields.

Technical Abstract: El Niño-Southern Oscillation (ENSO) is a large-scale climatic phenomenon that has fundamental effects on the surrounding terrestrial environments and associated ecosystem functions. Based on observed crop production and pest damage of a 41-y time series from 1980-2020 in China, the present study examined ENSO’s long-term effects on agroecosystems in different climatic regions of the Northern Hemisphere (middle-temperate, warm-temperate, Tibetan Plateau, and subtropical regions) and found that oscillating crop yields and pest outbreaks can ultimately be connected to ENSO cycles. During an ENSO cycle, the El Niño phase (the warming phase) and La Niña phase (the cooling phase) have had opposite effects on crops and arthropod pests in most cases, and such effects are climatic region-dependent. Our evidence demonstrates that climatic origins of a crop can lead to optimal thermal performance range-dependent responses to ENSO phases: for example, wheat – which originated from warm temperate areas – benefits from the La Niña phase when planted in subtropical climates and from the El Niño phase when planted in middle temperate climates; rice – originally from subtropical climates – are resilient to the El Niño phase in warmer areas, while the La Niña phase significantly increases the rice yield in the subtropical region. Similarly, corn yields are significantly lower during the El Niño phase in all four climatic regions, while the La Niña phase significantly increases corn yields only in the Tibetan Plateau region. We also found higher pest damage occurring during the El Niño phase and lower damage occurring during the La Niña phase for many of the arthropod pest species infesting these three crops. The stabilities of the different ecosystems indicate that wheat and corn have a significantly higher tolerance to ENSO phases than rice, especially in warm- and middle temperate regions. Our improved understanding of host plant and arthropod herbivore responses to ENSO phases can contribute to predicting the global changes in climate impacts on agriculture and food security.