Persistent decline of major insect rice pests in Japan over 70 years

Agricultural pests have long been central targets of crop protection, and recent climatic trends have raised concerns that elevated temperatures may have created more favorable conditions for outbreaks. We employed an empirical dynamic modeling (EDM) framework and applied it to exceptionally long‑term monitoring records of major Japanese insect rice pests to assess their temporal dynamics. We then quantified the impacts of climate change, as well as those of management interventions in paddy fields, over time. Across multiple regions of Japan, insect rice pests showed overall long‑term declines, with species‑specific temporal fluctuations. These declines were mainly associated with agricultural management practices, particularly pesticide use (notably neonicotinoids), and to land consolidation for infrastructure improvement, which appear to exert ancillary management effects. Increases in temperature generally showed negative associations with insect rice pests, although these effects were weaker than those of pesticides and land consolidation. Although some agricultural pests may increase in abundance under global warming, our results indicate that crop‑management practices such as appropriate pesticide selection and land consolidation play a more dominant role in maintaining pest populations at low densities in Japan. We anticipate that integrated pest management (IPM), which combines physical pest‑prevention measures with adaptive pesticide use guided by regular monitoring, will continue to mitigate widespread pest outbreaks in the future.